Light sources spontaneously not working in some chunks

That happens with chunks loading and unloading as I can tell, and with that also Entitys dups, and Observers stops working

Affected in 19w05a 😛

This bug is becoming much worse... Please fix it for the next snapshot, I have had it!

Affected devices on macOS 10.13.6

Added some logs and images as well. It doesn't matter what resource pack you use, the bug will still persist.

Exactly the same as reported happened to me, on many occasions. This is not a graphics rendering issue, the light sources are actually at 0 if you check F3. Mobs spawn as well. Only way to fix it is do as the original reporter said, replacing the lights. It cannot be fixed by restarting the game.

Problem still persists in 19w06a. I have some notes from my experiments that may help pinpoint this issue. I've managed to intermittently replicate this bug by going to the Nether, then coming out seeing the lighting missing. This happened 3 times out of 10 random tries. If I backup the region files before entering the Nether and then the lighting is missing when I return I can easily fix the issue by replacing those region files that were modified at the time I entered the Nether. The problem seems to occur when you enter the Nether and the game saves the chunks you are in. I currently could not find anything else effecting the lighting. If I enter and leave the chunks any other way seems to produce no issue.

First time this bug bit me was in 19w07a.  I've maintained and added to the same world save throughout the 1.14 snapshots without seeing this before.  Confirmed that a restart does not fix light levels.  Replacing the light source does fix the level.

I've had this happen to me in 19w06a once, but it was relatively minor. It happened moments ago in 19w07a, and was... not so minor. Torches, lanterns, and glowstone all had the issue in a rather large location. Like others have said, replacing the light causes them to be recognized, but otherwise they are not. Random lights are recognized, and always appears to be a perfect line where the light cutoff appears. 

In 19w06a, it was upon loading up Minecraft that this occurred. Exiting and restarting, as well as restarting server did not resolve the problem. For 19w07a, it was after returning from the Nether at night that this occurred. Again, restarting client and server did not resolve the issue. The location that is missing lighting is several hundred blocks worth, with seemingly random square of lighting that works.

Cave torches that I replaced yesterday in 19w07a are now reset to light level 0 after I visited the Nether today, even though I turned off the day/night cycle and the weather cycle.

I made a server on 19w05a and later moved it to 19w06a, in both versions me and my friends kept getting this glitch which is aggrevating too say the least. we had multiple creepers blow up entire portions of our base, and also after collecting the best trades you can get from villagers, a zombie spawned in the middle of them and killed them all. why is this problem still not resolved after more than a month after the first post. It ruins the entire server, because especially in late game when u have automated farms and sorting systems it's really annoying that creepers keep blowing them up.

I believe this is a (block-) entity related bug. Upon chunk loading, several blocks such as furnaces or containers stop working, light sources are all "de-actvited", and entities disappear and glitch. Hope this will get fixed asap !

Still happening in 19w08b, but it is bloody hell worse than the past snapshots.

Agreed, it is much worse in the 08 snapshots.

If you leave the grounds as a book, then return (like the map: https://www.planetminecraft.com/project/mrkaspersson-s-hogwarts-map-ultimate-continuation-no-download/) back to the grounds, that is how you reproduce the bug.

Happening again in massive amounts in 19w08b.

Game is almost unplayable due to this bug; if I leave what I've built and then come back, it will take 20 minutes to fix all of the lighting. Really hope that this is fixed soon.

I just found this post, I've been seeing similar light glitches in my buildings in my survival world. My underground railway tunnel went black, even though it's full of torches.

Does anyone know the typical cycles it takes for these things to get ack'd/resolved? I assume the problem should be widespread enough to warrant a fix or is there something I'm doing differently that's trigger this that can be worked around?

Well, boats we're broken for 5 years. I wouldn't hold your breath. Hypixel will come out and Minecraft will be dead. It's not like they got bought for billions of dollars or have the entire Microsoft team behind them to hire better/more devs.

Yes, I'm salty about another game breaking bug.

Confirmed in 19w09a.

Why is it that a light rendering problem so conspicuous can be delayed for so long?Can you see the past versions above?It‘s been there ever since 02a.It causes mob spawning,crops decaying,and is visually obviously terrible.Please fix it soon,thx.

Confirmed 19w09a for now.

Confirmed in 19w09a.

Confirmed in 19w09a. I hope it is fixed in Wednesday's snapshot as it make it impossible to play (at least on multiplayer). Besides this, I hope they will force a light recalculation after updating to the new snapshot, so I will not have to manually break and replace torches again. It is happening like 2-3 times a day and I have to go in creative and replace everything, or use fill to set the torches to some obnoxious block and then back to torches. Really annoying, especially because it is not a visual only bug.

It's sadly still in 19w11a 😞

Still in 19w12a

Confirmed in 19w13a. They might be planning to fix it in one of the final 1.14 snapshots, like a pre-release.

Confirmed in 19w13b

Confirmed in 19w14a

World where this bug happened will need to be fixed manually, by replacing the light sources, or by restoring the backups; Can you reproduce it in either a freshly created world, or in a world upgraded from 1.13.2 or earlier?

I just converted my 1.13.2 world (using the "Edit > Optimize" option in 19w14a) and the whole area where i logged in was set to lightlevel 0. I then went to check on one of my farms (to see if an issue i had is resolved in this snapshot) and the same had happened over there. Everything was set to lightlevel 0.

Replacing the torches fixed the light-level (but is really not an option as this would mean i have to replace hundreds of torches ans sea-lanterns in the world).

Edit: Just to see if the "Optimize"-function is bugged, i copied my 1.13.2 world and opened it without using Optimize first. Results are the same: lightlevel is set to 0. 

Upgraded 1.13.2 world to 19w13b, then upgraded yesterday to 19w14a.  Confirmed lighting issue.  Replacing torches manually is not an option when you think of worlds that are thousands of blocks by thousands of blocks.  It would be nice if there was a means to rescan lightlevels for entire worlds given past lighting issues.

Can you attach your world to the bug report?

If you need a pristine vanilla world, then we'll need to have one of the other watchers upload their world.  Our world was demodded with 1.12 and would not have reported an issue had their not been an existing ticket.  The zipped world backup is 4GB, so not sure if that is an issue as well and someone has a smaller example for testing?

I'm experiencing this on my small server world. 
It seems to happen pretty reliably when going back and forth between the nether and the overworld.

The world was created in an earlier 1.14 snapshot, but I can't remember exactly which snapshot it was.

If it helps, I have uploaded a single region file due to the 10MB limit, and screenshot, which shows the issue.  I originally noticed this issue teleporting to player builds, both of which showed this issue.

Edit:  Also, you can see that it also extends to lava, glowstone and nether rack light sources.

I can confirm it affects all light sources including lava etc. I strongly belive this all related to that elusive lava not producing light bug thats been occasionally showing up over many MC versions. Ive seen it in many of my games over the years, as recently as last week. When searching I can only find closed duplicates of this bug, there must be hundreds of reports over the years. Here is one. https://bugs.mojang.com/browse/MC-120980

A command that replaces/restores/renews all the light sources while this problem it's solved will be useful.

Hello there, I have been able to reproduce this on a fresh new world. This problem also occurs on my world that I've had and upgraded from 1.4 all the way through 1.13.2. Here are the steps I took.

• Generated the world using 1.13.2 with a random seed, named "MC Bug" and also a bonus chest.

• I placed down the available light sources one block apart.

• Set the world time to 19000.

• Backed up the world and loaded the copy in 19w14a.

• The light sources in the world did not show any visible block light on the F3 Debug screen.

• I backed up the 19w14a world again and loaded the copy.

• I then placed down a snow slab in front of one block to cause the block light to update.

Please see the 3 attached worlds to see the progression of the bug. If there are any issues please let me know, thanks.

Still happens in 19w14b but now the blocks where the torches are placed also LOOK like they are  illuminated. But the lightlevel is still 0.

Here is a screenhot:  

I think they might fix this 1.14 snapshot lighting bug in a pre-release, like they fixed the 1.13 snapshot lighting bug in a pre-release(1.13-pre5).

still happening in 19w14b- I found that if you place a lantern near them, The lights will then function. You can remove the lantern, however it only affects ones in its light range.

F3 shows them as normal light level, they just aren't generating the light.

the picture shows before and (inset) after. You can see from the back of the inset pictures torches which are out of range of the lantern i used.

Confirmed in 1.14-pre1

Can you provide instructions to recreate @Digit1704? This was marked as fixed in 1.14-pre1

See [MC-147776] for 1.14-pre1.

In 1.14-pre1, I am not sure if it still recreates itself, but previously mislighted chunks (light level 0 regardless of having light sources or not) stay mislighted (if its a word). Replacing the light source one-by-one is not an option as the bug affected thousands of metre squared in my world. To mark it fixed, can there be a way for the game to refresh the lighting server-side while loading in, or provide a command or F3-something.

I just came online in the new snapshot, lights I had replaced to get it working, only to find now that again some of the lightsources just don't work.

Try converting the world to 1.14 pre1 using the "Optimize World" function and make sure to enable the "Erase cached data" option. This should rebuild all height- and lightmaps. After doing this, my world was back to normal.

Where do I find d optimize world function
And how do I enable that option

Actually confirmed in 1.14 pre1, I downloaded my multiplayer world back to my computer, put it to singleplayer and run the "Optimize World" function in 1.14 pre1. Uploaded it back to my host, and joined the game. A lot of the originally mislighted areas were fixed but this is new: (refer to lighting again.png)

@BladeCP69925233 Read my comment after you
and also it now plays the sound when you are near a dark cave

@brandon In the single player screen select your world but dont double click. Then click edit and the optimize world option is there.

Still happening in newly generated worlds.

Can also confirm that this is not fixed.

I can triple confirm that. I left the overlord and came back and I saw the lighting get messed up. This newly formed after the fix. see screenshot 

. Its like random chunks gets lighting turned off, other chunks are fine.

As an FYI. That occurred on a fresh world I made on snapshot 19w13a. I had no lighting issues until just now running on 1.14 pre release going back out of the nether.

Luckily optimizing the world fixed that lighting issue I posted.

Note: This isn't just a bug with light sources. Chunks that have no light sources in them will appear pitch black during the daytime at the surface level

The problem has escalated. I had a problem of MC-147877 (Namely 1.14 Pre1 resetting some of my chunks), so I took the original backup and decide to make my server fall back to 19w14b, which is when the backup was last used. Now throughout my world, not a single kind of light source is working. The game is basically unplayable now in normal survival as mobs spawn everywhere. (i was in spectator)

I run the server with the command below on 1.14 pre-release

java -Xmx4096M -Xms1024M -jar server.jar nogui --forceUpgrade --eraseCache

And all the chunks with light issue is fixed perfectly

I can confirm that too.

Yesterday I want to play with my Friend. We generate a fresh standard world.
He was the host and saw these dark spots.  But for me everything looks good.
Then we decided to switch .. I take the savegame and host the game.
Now I have dark spots and for my friend everything looks good!

strange...   Perhaps this can help too..?!

and sorry for the grammar, I used a translator for this 😉😛😃

This bug has not been completely fixed in the 1.14 Pre-Release 1.

Adding my own screenshots for 1.14 java pre-release 1. Might be a different issue as it behaves slightly differently. The dark chunks I had aren't updatable. Putting a torch simply acts as if there is a structure above outlining the entire chunk.
Suggested fix not applicable to singleplayer world. Game breaking bug as far as I can tell

Please provide the reproductions steps if you can, I can't trigger it myself on a fresh world in 1.14-pre1.

@Georgii Gavrichev simply create new amplified world and fly around

I have a 1.13.2 realm map that I opened in 1.14 prerelease 1. I believe this is at the edge of the transition from 1.13.2 -> 1.14 world, but not 100% sure that this is the edge. I converted the world to a 1.14 prerelease world before opening.

See:

MC-147985 provides these steps to reproduce:

1. Go to nether.

2. Return through nether portal at night.

3. Go to bed.

(I haven't tested this myself, just copying this here for visibility)

I confirm this annoying lighting glitch in Minecraft version 1.14-pre1. Dark shadows are randomly placed all over the world.

I can confirm this issue on my map I've created. (If you need it: https://www.dropbox.com/s/m9gv3jsf8r55r89/Xiphias%201.14pr1-19.04.11.zip?dl=0)

I cleared the chunk cache and then flew around some areas to make sure they were all loading correctly. Just flying around in one area on a second pass lighting glitches appeared where they weren't before. Quitting and relaunching a server with the map caused the generation of light glitches - and sometimes where the issues were changed.

Can confirm for 1.14-pre2. Actually since pre1, the lightning bug has a totally different effect than on snapshots: now it's noticeable by large 1 wide dark stripes affecting blocks that are supposed to have a sky access (the sky light value is falsely equal to 0).

Can confirm for pre2 as well, it happens on the multiplayer server I'm playing on.

Can anyone reproduce this (whole chunks being dark - not just a single column, that one is being tracked in MC-148037) in a world that was not created or opened in 19w14b or 1.14-pre1? (i.e. created before or after, and not opened in either of those versions)
(sorry about the confusion)

This has happened to me in a world that was generated in one of the first snapshots. It happens to other players but few as bad as me. Seems I made a poor choice in chunks, though as you can see, I've had the whole nether go dark as well. There are huge dark spots in our nether.

Following the instructions to refresh the cached files made the problem worse. The refreshed light sources never stay lit, they will go dark again.

I haven't had the problem since I ran the "optimize world"-fix. 
(Side note: holy poop why are there so many status updates on this from the past hour? my email is getting spammed)

I have a world updated from 1.13.2 and cannot tell if it's a lighting error or the pistons. It's the only dark place I've noticed and it's the room with pistons over jacks o' lanterns.

1.14-pre2. World has been transferred from 1.13.2 and "optimize world" feature doesn't seem to help with this issue. After first attempt to transfer this world there's been dark chunks on the lake (fourth screenshot) but not after second transfer (third screenshot)

edit: during first transfer I tried to optimize world (with checked "erase cached data"), but not during second one

We had been playing on the prerelease for a little while (starting a LAN server at 19w14a I think), then one of us entered the nether (had updated to pre-release 2 at that point). When they came out we noticed this problem. Only seems to affect sub-chunks around the nether portal, if you go out far enough they don't seem to occur

https://twitter.com/HorzaPanda/status/1116747514089230336 has some of the screenshots we took.

Biggest difference I can see between us and other is we didn't have this happen on updating the world to pre-release 2, but after doing a thing (interacting with the nether)

Can confirm, generating a new world on singleplayer or multiplayer results in random chunks spontaneously turning dark from top to bottom. Optimizing the world and clearing the cached data temporarily fixes the issue, but not for long.

Edit: Added screenshots with F3 open + newly generated world on 1.14 Pre-2 with glitched lighting

1.14 Pre-2 world with glitched lighting

Update my map to 1.14 pre1 to pre2 do the same thing.

I've been using 1.14-pre2 for a while now, and haven't encountered this issue under any circumstances - so I am suspecting hardware-related issues (though this would be confusing, since it's not a visual glitch, but the actual lighting level is missing).

If you are experiencing this bug, please provide a screenshot of the problem occuring on 1.14-pre2 with your F3 screen open - on a world that was never opened in 1.14-pre1 or 19w14b.

EDITED

@[Mod] Galaxy 2Alex: Oh, thank you. My fault. Will this bug get fixed too? Maybe it kinda connects to this bug, it still is some kind of lightning bug 😃

@Wild Katz: That bug is MC-148037.

Screenshot with F3 screen. Also, I cannot reproduce this bug while in singleplayer mode

I have this, on a world that was previously opened in both 19w14b and 1.14-pre1 (the world goes all the way back to Beta 1.3_01 and was fine until the 1.13 snapshots when problem started, that still persist even in 1.14-pre2), and in addition I've also seen random chunks get entirely regenerated.

I can confirm this is still an issue with new worlds created in 1.14-pre2. See

.

I attached the world as well,

. Just in case you don't spawn near the lighting error, use the following command to go there:

/execute in minecraft:overworld run tp @s 9806.51 97.99 -2.50 -231.52 33.91

Is there a way for developers to simply add a debugging f3 combination/command that updates/ensures all light sources (say around a player) is doing their job server-side? I know this is not a permanent solution but I think it might be good enough for now, as replacing light sources (including lava) is a tedious manual thing to do, and it shouldn't be a difficult thing to implement (I guess?)

After some testing, I discovered that flying back and forth on full spectator speed in a redstone ready world can very very rarely reproduce this issue. I then tried the same thing on a different, much slower hard drive, and was able to reproduce it much more reliably - so hard drive speed may be a factor here.
I think this issue occurs when a chunk gets unloaded, but while it's unloaded is getting loaded again, messing up its light level values.

Unlike the old lighting bugs, placing a light source in these areas does not fix it, instead it acts as if the area is under ground.  Mobs spawn, and light level from the sky reads as 0.  We lit up one of these areas at one point, only to return and the torches were no longer giving off light. 

Oddly, in creative I found that these dark patches have different heights.  One black chunk flying to 96 height the sky light read 15 again, another was 113 height.  It seems to be acting as if there are invisible blocks preventing light from reaching the lower levels.

My wife and I created a server using a 7200 rpm hard drive, this was also created yesterday using the 1.14 pre release 2. Everything was fine until we logged into the server a few minutes ago and we saw all this darkness (2019-04-13_18.38.32.png). I tried updating the chunk but nothing happened. We even tried putting down light sources and nothing happened.

I loaded up the world that [Mod] Neko provided. I have a pretty steady computer, Int i7-7700HQ, GeForce GTX 1050 and I received the lighting bugs. They don't look like any other as mobs actually spawn there!

The following solution worked for me and my friend:

Select world > instead of "Play selected world" > "Edit World" >

> Optimize World > tick box for "Erase cached data" and proceed

we are already playing for a few hours now and we don`t have dark spots anymore

If I go above lvl 94, I see the sky light back to level 15

If I go back to lvl 94 and lower the sky light lvl is 0

Can I ask you where you can find the "Optimize World" function?
We would like to play but with these dark spots its very annoying.

^Click a world then Edit.

The new erase cache data from the optimize world menu is useful as it forces the light to be recomputed, so it permits to solve any existing lightning issue. But still with pre2, dark patches seem to randomly reappear over time, at least from what I have seen, outside of Spawn chunks. Maybe picture (Neko's world attached)

suggests that this glitch has something to do with chunks loading?

I've created three new worlds in 1.14-pre 2 (two normal and one amplified) and I've invested several minutes flying over each one, and I've not been able to find any black patch related to the lighting, so it seems to be fixed for me = D

I can give another example that seems to confirm that this issue is related to chunks loading. First these dark patches never appear at the same location again after cleaning the cache. Second, I had these patches appear at my logging location (outside of spawn chunks). Yet, the last time I was on, those patches weren't there.

I had the problem multiple times by putting blocks in another chunk in an empty flat world (The void preset).
Here is the video:

Note: Sometimes, in my case, a simple disconnection/reconnection to the world is enough to solve the problem (before it starts again...). But it is not always the case.

Also, the light problem affects the mobs.
Here is an example with zombies that should burn in the sun:

It's kind of weird that I created my world in early 1.14 snapshots, and still don't have this bug.

I can reliably recreate it by killing the server quickly without giving it time to save everything properly. Next time I log in, there will be shadows around my player.

For my server its almost as if the darkness is spreading it started with 1 or 2 spots around my base and now my entire island is dark and mobs spawn even during direct sun. Its been 3 days and the creepers are still there send help.

I had this issue with a map I created. I replaced the region data from a previous backup that wasn't loaded in 1.14-pre1 or 19w14b. I now see no lighting issues.

I tried the same files from my map (that are now working in single player) in a pre-2 server and there are still lighting glitches there.

I discovered the cause of my issue. Happy that my map was loading without lighting issues I ran it through the "Optimize world" option with "Erase cached data" checked. This re-added the lighting issues into the map. Reverting back to my fixed version and running that with the server resulted in no known lighting glitches.

This is not resolved. Today (4/16) while playing the single player world that I thought was fixed, lighting glitches appeared after visiting a previous area that had none.

I don't know if this is seed related, but I can reproduce this issue every time I try in 1.14 pre 2, by doing the following:

• Start a new world with cheats enabled, with the following seed: -2848667230427644371

• Do /gamemode creative

• Fly straight up to Y-level 110

• Do: /setblock ~ ~ ~ minecraft:dirt

• The dirt block will get light level 0 (the whole chunk will actually get sky light level 0 at that y-level)

The same exact thing happens running the same setup at a dedicated server.

It is marked as fixed in future version, which is the next pre-release. So you'll have to wait for it. You'll probably have to use the new erase cache function to clean your map.

This issue is definitely not resolved. I had the problem on a world that I wasn't sure which snapshots has been running on so I tried to reproduce on a fresh new world created in 1.14-pre2. Only 4 minutes after world generation I found a buggy spot. For some reason, there's a void from y=94.5 to y=110.4 in certain random areas where the sky light drops to 0 and the player character goes pitch black accordingly.

Video from creation of the world to the bug showing up: https://youtu.be/-GXOzrF8RRw

Detail of the height at which it triggers: https://youtu.be/1Rg4CX0Gh70

World seed is 7985723480508602877, although it shouldn't be related to the bug as I just showed it's a random fresh new world created in 1.14 pre 2.

Fix Version/s:
Future Version - 1.14+

This issue will be fixed in the next pre-release. It's not fixed in 1.14-pre2 yet.

Yep, definitely not resolved. In 1.14-pre3 the darkness is gone - that really fine, but... In those previously dark chunks mobs are generating even in the full sunshine and zombies, skeletons and drowned do not burn. Spiders attack during the day. Mobs generate next to torches, so the lightning problems continues 😞
See

In Minecraft 1.14 Pre-Release 3, try using the new 'Erase cached data' option for worlds that have been generated in previous versions and see if the issues persists.

Any way of doing that on a server? Issue is still there - while I'm sure a cached data will reset it, I also don't want to delete the entire region file to fix it, if possible.

And how do I "erase cache data" in java edition? 

How to erase cached data.

• On singleplayer: from the loading world screen, click Edit, then Optimize World and check the erase cached data box before confirming.

• On servers: use the archive options

  --forceUpgrade --eraseCache

Please keep in mind that this bug has been fixed for worlds created in 1.13.2 and before and not opened with any 1.14 snapshots, as well as for worlds created in 1.14-pre3 and beyond. If you can still reliably reproduce this bug with such worlds, please leave a comment and we will investigate.

Will the server startup flags need to be used for one start-up, or should those remain in the startup file indefinitely.

Running my server (1.14pre3) with

--forceUpgrade --eraseCache

fixed the issue on a world played on previous 1.14 snapshots as well.

@unknown You only need and should anyway only use these options once.

Thanks for the reply.  I was hoping it wasn't world loading dependent and was just done at startup.

Im happy to hear that the lighting bug seems to be finally fixed, but by optimizing world/force updating I encounter MC-148147 and it just fails on me (at 52% or 34%). I know my world might be corrupted somehow but I believe there was nothing I have done that was not intended to be done - I never killed the server apart from it crashing etc. I know this is not related to the lighting bug anymore but without optimizing the world/force updating the lighting situation would still be the same.

Will worlds generated in the 1.14 snapshots with dark chunks not receive a fix? I'm glad the issue is fixed for new and 1.13 worlds but the issue still persists for recently generated worlds. Force upgrading/erasing cache for 1.14 snapshot worlds works at first but when the world is reloaded the problem comes back. Reloading dark chunks will appear to fix the issue however mobs will still spawn and not burn in daylight as if the sky light level and the regular light level were 0.

As per the previous comment mobs do not burn in chunks that were previously dark. Server and client light levels in chunks are correct at 15. Mobs will start to burn if they move outside of the chunk and then stop burning when they move back in.

Edit - Raised new bug

I fixed it by resetting  my gamma

Tested this morning with a 1.13 world that previously experienced the issue.  I was not able to reproduce the issue with world loads, teleports, portals or flying around the world.  This additionally fixed some older dark spot issues we had.  Thank you!

had this issue in pre 1 and 2, tried pre-3 this morning on our server and all seemed good, its now afternoon and i went back on only to see the dark patches again, torches there but no light, and mobs able to spawn there.

Did you follow the instructions in the description above for fixing worlds created in snapshots and pre-releases prior to 1.14-pre3?

I opened a map with this issue in pre-3 and it resolved. I followed the instructions above after (Singleplayer: Select world → Edit world → Optimize world → check "erase cache data" → Backup and load) and few around in creative with no issues. I then played for half an hour with no lighting issues. Pre-4 is out now, I will post a follow-up if I see the issue return.

Hello, this seems resolved for the most part, however, I did run into the odd case of this occurring in the nether in a single chunk around my portal today. However, the issue does seem to be resolved.

This hasn't been resolved and this better be fixed in the new patch this has gone on for too long now and nothing has been done about it.

@Brandon: If this issue still occurs for you, please keep in mind that this bug has been fixed for worlds created in 1.13.2 and before and not opened with any 1.14 snapshots, as well as for worlds created in 1.14-pre3 and beyond. If you can still reliably reproduce this bug with such worlds, please leave a comment with steps to reproduce and we will investigate.

hi im not great with server controls but you said to fix it do this, Multiplayer: Start the server.jar with the following command:

java -jar server.jar --forceUpgrade --eraseCache. how do i do this on a rented server?

It would be best to contact the support of the server rental service that you're using. Alternatively, you can download the world onto your computer, move it into your Minecraft world folder, and then follow the steps for singleplayer. After that you can move the world back to the server again.

I've got a 1.13.2 world that i converted to 1.14 pre 4 yesterday (using the Optimize-function and with the Delete Cached Data-checkbox enabled) and while lighting was OK when i converted it to pre 5 today, torches stopped working after i went to the nether and back a few times.

I then deleted this world and converted a backup of my 1.13.2 world to pre 5 - again using the optimize-function with the "Delete cached data" enabled. And again: lighting was OK for some time but after going to the nether and back a few times, torches stopped working again.

So far it seems that i can somewhat reliably reproduce the issue at my wither-skeleton-farm which is kinda special as i push skeletons into a portal to kill them in the overworld. So what I do is, I AFK for a few minutes in the nether (during this time skeletons will go through a portal every couple of seconds) and then go to the overworld myself (using a different portal). And after some time, the torches break. Sky light will be 15 and Block light will be 0 (during the night) for the torches.

I will do some additional tests tomorrow to see if i can gather some additional informations.

Edit: You can see this bug happening in the latest video by LogicalGeekBoy (https://www.youtube.com/watch?v=VHXi1dhntvI) at 16:20 -> and at 25:45 you can see that he is using the pre5-Version

Can confirm that this issue exists in 1.14-pre5 even after using the optimize function and deleting the cache. After traversing a nether portal, multiple chunks of my base are not receiving light. See screenshots attached. This issue was not immediately prevalent and only happened after traversing the nether portal a few times and after being in the game for a few hours.

Edit: Travelled even farther from my base and found even more chunks where the glitch is happening:

I still have the same server problem every time I reload the chunks.
And even after doing the command to force the lights.
Minecraft Pre-Release 5

Reopening because of the above comments in this ticket and a new report about the issue (MC-149071).

still getting this issue in 1.14 full release. we updated from 1.13.2 to 1.14 full, optimized world and cleared cache, but it is still happening, please sort this out.

I am also seeing this in 1.14; we updated from 1.13.2 to 1.14 full release.

EDIT: I applied the fix outlined in the bug header and it fixed the lighting bug for me.

RE-EDIT: The bug returned after a while, and I suspect this will keep reoccurring.

i hope we aren't going to have to wait months for 1.14.1 to fix this issue, its pretty much game breaking and was known about in all the 1.14 pre-releases

Same here.  World originally created under 1.8 or some such, worked perfectly up to 1.13.2.  With 1.14 full release torches do not light the surroundings, thereby spawning my (underground) bases full with monsters.  Not nice, unplayable.

System: Linux Mint 19 Cinnamon, OpenJDK Runtime Environment (build 11.0.2+9-Ubuntu-3ubuntu118.04.3).

Above procedure to fix world DOES NOT.

Edit:

To make things abundantly clear:  this world  was NEVER opened in any prerelease and is not modded.  My system has an SSD, so I would be flabbergasted if disk speed was an issue.

I just play in 1.13.2 until this bug is fixed, long as it may take.

 Edit:

In my case this happened after returning from The End, not using a Nether portal.

It is in Realms too (it's the same release 1.14 after all). Is there a workaround for this case?

As of 10:30 Am eastern time this glitch still exists on 1.14. I just logged in and my torches were not putting off appropriate amounts of light. I logged off before the creepers got my base chests again. Frustrated.

Let's see if I can add something to the conversation.

Playing the full release (1.14) I have had this glitch on my friend's private server as well.

She ran the fix and the fix worked, this however was a temporary fix, not permanent.

I believe she ran the fix three of four times already which in all occasions definitely had it's positive effects, however they were immediately cancelled out a days later (or a number of hours later)

Sadly I am unable to contribute much to fixing the bug myself since I have as much experience with technology or coding as an actual bug does, I can test out the fixes provided with my friend to see whether they work or not, and give the specifics if they work, and if so if if seems to be working permanent.

To let Mojang know about the severity of the bug compared to others, look at it like this.

I have nothing against having housemates, if anything, can be fun even, many would (I hope) agree.

Unless those housemates try to shoot you, strangle you or blow up in your face.

I hope a fix will be introduced in the 1.14.1 release, it would make many happy experiencing the bug at this moment.

I have loaded a 1.13.2 world using 1.14 server.jar using the cache clearing method described by the moderator. 

After a few hours or after a restart, the lighting issue is back.  Am I supposed to add

--forceUpgrade --eraseCache

to my java server start command from now on?

This keeps coming back and has made my world unusable.

@unknown Normally you shouldn't use these options at each start as cached data help running your world faster, as you don't want your world to always recompute light on each time you visit some chunks again. But as currently this bug persists, I suggest you to do this step whenever the lightning issue becomes an problem.

I must add that so far I haven't seen this issue on my world which was created on 1.14. This issue seems to only concerns conversion of old worlds. If it's the case, then the issue is different from the one that was originally created for 1.14 snapshots. Maybe you should consider cloning this ticket for clarity.

I optimised my survival world a couple times on the official release, and the lighting seems to be stable there now. Other than chunks loading at an odd rate, things are running pretty smoothly. I spread out pretty far across the overworld as I moved through the snapshots, building settlements tens of thousands of blocks apart, so I optimise the world at each faraway settlement which still has unloaded lighting glitches.

The issue seems to be that some chunks or objects load with a negative lighting value so instead of propagating light, it propagates darkness. I haven't found precise repro steps as the issue does not always occur in the same locations. Could very well happen during loading of the chunk.

The issue can be observed on torches that generate darkness. The torch block's lighting fx is not affected but the propagated light is. Knocking it off and setting a new one fixes the issue but not permanently. The bug might pop up again when the chunk gets unspawned and reloaded.

I have also had the issue pretty steadily with my monster spawner. The enclosed area on top of the drop should be pitch black but it often loads as full daylight. Again, loaded with a negative or inverted lighting value.

The issue is pretty easy to repro just by loading a world and walking around it. Torchlit caves or tunnels make it particularly easy to spot.

edit: Playing on a 1.13.2 world that was patched to 1.14

I've noticed that only block lighting is affected

@Johnibur - I too am working with a world brought from our 1.13.2 server.  We have tried the cache clearing numerous times but the world is now zombie city.  As such we have created a new world in 1.14 and are not seeing the problem.  We are sad.

So this seems to confirm that this issue only affects converting old worlds.
@unknown They might find a fix for your world in future 1.14.1 release.

@Johnibur unfortunately I don't think that is correct. We have a world created in the 1.14 pre-releases and are having the same problem. If the cache is cleared on startup, the problem goes away for a while, but always returns.

I confirm the issue for 1.14 generated map, I have a server with a 1.14 generated map and this issue appears

Experiencing this issue as well.

Playing on Realms (and it is not my realm, so the single-player temp fix is not an option).

Realm was created in 1.13.2 last September and I use a Win7 machine.

Have this issue as well, suddenly! 1.13 to 1.14 and worked since release and now suddenly!

We are having this issue on a Realm as well.  1.13.2 to 1.14, (it is a realm so no pre-releases)

Replacing the affected torches fixes the issue in the area until the next time the chunk is unloaded at which time it seems to come back.  It only affects some chunks and in at least one case replacing the torches with sea lanterns seems to have made it go away... The problem is there are hundreds of torches.

I have the same issues,  I am on a server and when I logged in my ware house/farm/etc became partially dark. Replacing torches helped but then it later when I logging in I got the same issue again.  Playing on hard + replacing all torches everytime is certainly not an option. Also it is expanding to other players on the servers who have the same issues.

every time i load the server more lights are out - its unplayable at the moment on survival as mobs spawn in the rooms and replacing the lights every time is not an option. anyone got any suggestions on a fix? i dont host the server so i dont know how to clear the cache 

[Possible cause found]

An update to the glitch from my former post, been playing Minecraft on the Private server and paid close attention to the moments when it happens.

The Lighting occurs /activates for me at least everytime someone goes offline while I am online, so if 2 people are on the server at once and once goes offline the glitch will occur when you log back in or get back out from The Nether.

I don't know when others pay attention to this and try it out if they observe the same thing as I do, the glitch just occurs specifically at those moments.

When I know 2 people have been online at the same time, after one goes offline glitch occurs.

I hope others could either debunk this for them or agree with me as well to what is the cause of this issue, addressing the cause can help Mojang fix it for 1.14.1

@Marilyn it only happens for me when I log out but maybe that's also because no one is at my region?

Someone had this issue around his nether portal destroyed it and the issue around the nether portal was fixed.

@konnichiwa You may be up to something here, I will try shutting down the Nether portal and see if it will be fixed.

I question it though based on the range of the issue and some screenshots posted, worth a try though.

This has gotten steadily worse since starting a new Realm on Tuesday. My entire base is now affected and mobs are spawning all through it. It's completely unplayable now. Even lava no longer glows. Please, please fix soon.

Also experienced on Realms today.  Played every day in the past week since the release without incident after upgrading from 1.13.2.  My entire base is a gigantic mob farm now, completely unplayable.

This is prolific on Realms and is breaking so much of the game. I have old cave systems which are now spawning monsters again, affecting rates of mob farms and endangering villagers, etc. Also all of my 'safe' places (i.e. base, storage, etc.) and constantly infested. It's making the game very tedious to play since I have to light everything up multiple times per day. This is SUPER important to fix soon, please.

After re-lighting my base on a Realm, the problem occurred again after I disconnected and signed back in.  I traveled to a guardian farm about 1000 blocks away and the lights were out there as well.

In both cases, the affected area was at y=5 and the sky light level was 0.  Even while standing on a platform of sea lanterns, the debug screen showed the block light level = 0 and mobs spawned on the sea lanterns.

I don't understand how you got the green light to release with this bug that has existed in snapshots. it makes the game unplayable and i kind of wish it was possible to get some kind of refund on a realm since its just wasted time now since its completely unplayable and it feels like i was basically scammed.

I relit my home twice for it to happen again only a few hours later... not going to be playing until this is fixed.

I play on a multi player server and am having this issue happening at base as well. Mining tunnels are dark except for the block where the torch is. Everywhere else registers 0 light. I popped into my storage room the other day where torches have been spammed and was greeted by a creeper. I can stand diagonally one block away from a torch and have that block register a light level of 7. Sure there is a temporary work around as described above but that's not realistic when you play with other people to have to reload the jar every time this happens. Nor is it realistic to have to re-light your entire base every time this happens.

Using Ubuntu and the java server 1.14.  Ran the --eraseCache.  Things seemed better initially so I removed the switch.  Now it's back, so I stopped the server, added the --eraseCache back into my java launch and the problem is still happening.  Seems like whole chunks are affected while others aren't.

Any kind of update on this since the game unplayable until its fixed?

Tarek, not sure why the game is unplayable. Did you follow the instructions from the moderator to fix the lighting? I had the exact same issue and the procedure fixed my lighting issues like a charm. The occurance of this bug is not very frequent as it used to be. At least I have not managed to get it to happen in the past month or so.

REALM server i play on its coming back each night

• go back to my house its a death trap now , and the bug seen to be like a chessboard .

well dinnerbone said they were hoping to get a beta of 1.14.1 done by the end of the week or early next week so my guess is that, thats the earliest we may get a fix, but seeing as it still says unresolved and wasn't fixed in the pre-releases im not getting my hopes up. my faith in mojang has severely diminished with this update as, like tarek said it does make the game unplayable and it shouldn't of been in the full release after not being fixed in the pre's, which as far as i understand is the whole point of having pre-releases. the least they could of done was to have fixed this asap and put out a hotfix, the other bugs are still a pain but they dont make it unplayable like this one does.

@Daniel Tavares are you joking? That "fix" is about ad much if a fix as replacing the torches just slightly less annoying but still very annoying and arguably more of a pain if you play on a realm server. This bug happens every day when I log back in and if only gets worse as more parts of the world breaks. Villages are also basically impossible to protect now. My house keeps getting blown up by the 20 creepers inside of it. I dont know what you do in minecraft but the game is very unplayable right now

I play hardcore survival. And im not having those issues. There might be a configuaration on that server thats exagerating the issue. It seems to come about when the game is saving chunks when going between dimensions. Sorry to hear its that bad.

For those who have this issue and claimed not being able to play because of invading mob, a quick workaround until this is fixed is to turn the difficulty to peaceful or to disable mobs spawning.

Anyone know a fix for Multicraft (or other) server managers?

We started a new world during the snapshots and experienced this bug a lot through the pre-releases, making it very hard to play and build sustainable structures due to mobs spawning.

We tried the fix suggested over and over again, just to experience the issue coming back and sort of spreading to new chunks. Been following this issue since only a couple of watchers and has seen it grow and impact so many people.

Due to the overall performance of chunk loading, making elytra flying almost impossible, relying heavily on Nether portals for transportation, we decided to upgrade our server at CubedHost to see if it would get better. Tweaking GC settings and running the eraseCache every now and then, things didn't get better until we lowered our server View Distance on a wim, from 16 to 10. And presto, chunks that have been dark before now works and we have yet to experience the issue again.

I really hope this experience can help Georgii or some other developer so that we can safely rely on light sources again to stop mob spawning – which to me is a core mechanic of the game, that is now broken. So looking forward to 1.14.1! Go team!

As much as i love mojang, it would be nice, considering how bad this bug is, if we got some kind of acknowledgement from them about it, and perhaps an update as to how the fix is going because it seems to be taking a very long time and is causing a lot of grief for a lot of players.

Is it possible to get some insight into what 

--forceUpgrade --eraseCache

actually do?

I assume forceUpgrade is upgrading to the 1.14 chunk format, and I assume eraseCache is deleting some cache of some sort. Is it safe to do this even when the server is 1.14 and I've had to run this before?

Executing this caused half of my world to dissapear when rendered with Overviewer. I am unsure if that generated world still exists or was deleted from the system and only player location chunks were kept.

Yes, --forceUpgrade upgrades all chunks to 1.14. --eraseCache erases the lighting values saved in the chunks (maybe some other values as well, I don't really know) and re-calculates them as soon as the chunk is loaded the next time by the game. It should be safe to use, but just to be sure, create a backup before.

I don't really know how Overviewer works, so maybe it considered chunks whose cache has been cleared as "hasn't been generated yet". This would probably be an issue with Overviewer, and not with Minecraft.

I play on a Realms server, and I've been getting hit hard by this lighting glitch. It's annoying having to constantly replace light sources , and it's absolutely unacceptable to have strip mines and villages overrun with monsters simply because light sources bug out. While erasing cache data helps, it's a cumbersome enough process that our server owner is only willing to do it once a week. Frankly, I find it astonishing that Mojang didn't bother fixing this problem before releasing 1.14, and so far it's been giving me constant headaches. 😞

I upgraded from 1.13.2, but noticed this bug in my base with all of my chests of enchanted books.  with it being pitch black, as soon as I moved far enough away creepers started spawning and griefing my chests.  I restored from backup, but later noticed that even rebooting the server didn't fix it.  Now that I read that the bug has been found but no resolved, I'm going to downgrade to 1.13.2 and perhaps re-upgrade on a more stable build.

Just wanted to mention that I've just experienced this on a brand-new 1.14 world on a Realms server, so it doesn't require you to upgrade a world created in a previous version. I don't know how or why it happened - I logged into the server into a torch-filled area with light-level 0 and a bunch of mobs.

Another report of this issue. We started our server with a snapshot in March (I'm sorry I don't know which one). This issue first popped up for us after a few weeks.

We do not have access with our host to modify the java command line options.

It takes 20 to 40 minutes to download apply the fix locally and re-upload the server, but it only takes minutes for a chunk to go dark.

After manually replacing every single lantern in our villager packed library a couple times I decided to look into automating the relighting process.

What I've come up with is a datapack with a function that when executed:

1. Sets difficulty to peaceful

2. Summons an armor stand to serve as an anchor for the rest of the commands,

3. Moves the armor stand to the corner of the player's current chunk

4. Replaces common primary light sources (torches, sea pickles, sea lanterns, glowstone, lanterns, end rods, jack o lanterns) in that chunk with place holders (various types of dead coral fins) 

5. after a few ticks restores the place holders with the appropriate original light source.

6. deletes the armor stand

7. sets difficulty to normal.

It seems to work reliably for everything  as long as the light sources are not packed immediately next to each other, If you have jack-o-lanterns or sea pickles packed immediately next to each other, you risk losing some of them.(I expect the same behavior from some configurations of end rods, but we don't have any yet.)  (I understand why this is happening, and how to prevent it, but I don't currently have time for further refinement.

I'm willing to make this available in it's current form if anyone is interested.

I also found this problem too. I have log in to my server on afternoon, and everything are working normal at my house. But when I log in again in the evening, this bug happen. My house turn dark, other area in my house' garden too. It happen to only some chunks, not all. And when trying to replace the torch/jackolantern or place new one, it's become light. I run the server for a group of Minecraft fans in my country. So this bug impact more than just me. I hope the core of the game update to fix this bug soon. Thank you.

This pic from my strip mine which impact a lot from this bug.

Noticed just today: I'm underground but Sky light level is 15, and zombies start burning.

Happening on my Realm as well.
Martin Piper, could you make your datapack available? Sounds like a good temporary solution

Tobias Kristiansen, I've attached it here.

to use:
/function relight:me
again uses various types of dead coral fans & dead coral wall fans as place holders. If you use these in your builds, you'll want to edit the functions relight:me and relight:on to use different placeholder blocks

As a warning and for additional info, when I ran the recommended workaround (download, optimize world, upload) on our realms world that was first created in 1.14, it reset everything in the spawn chunks. Not just the lighting, everything we built/placed/mined in the spawn chunks was gone.

Confirmed for 1.14.1-pre1

Confirmed that this is currently breaking our vanilla 1.14 server as well. I need to apply work-around mentioned above every few days or so. Causes about 30 minutes of server downtime per instance (problem grows larger as our world gets explored more).

seriously? theres a 1.14.1 pre release and this bug isn't fixed? why fix little bugs first when theres game breaking bugs like this?

Because game breaking bugs generally take more time to fix than little bugs.

i agree they do, but the bug has been on going since the first 1.14 pre-release so its not like they haven't had time, perhaps if they just gave an update on how the fix is coming people would be less annoyed.

Does this still happen in 1.14.1-pre1 with either a new world, or a world with an erased cache? Please keep in mind that it's possible to trigger it, close the game, but not see it until you load the world the next time.

This bug is taking so long because we have not found any way at all to trigger it on demand; I never manager to trigger it once on my machine, and there seems to be no action in particular that makes it more or less likely to happen; a few potential causes of this error were fixed in 1.14.1-pre1, but without being able to check there's no way to know for sure.

Georgii if it helps, this tends to trigger for me when I reboot my server. My server is hosted at Apex using multi-craft interface. Every time I reboot, the more torches go out each time. that's when I notice. It seems to be elongated over time thing.

1.14 or 1.14.1-pre1? One of the fixed issues was for the server shutdown code.

1.14 Vanilla

Georgii. I did the fix on my realm server, copying it into singleplayer and then reuploading after erased cache. It fixed it for 1 hour, and then it happend again.
I assume realms run the newest version of 1.14, so yes it is still a problem.

Side note: The PRE-RELEASE states it has been fixed. If you are playing on Realms, you have NOT received the fix yet. Realms only runs full versions, not pre-releases. Don't report it as "still not working" if you're on Realms.

I have a full prod server on 1.14 right now, so I won't be able to test reliably myself. I hope it gets fixed soon, if it isn't already. 🙂

I did the force upgrade, and the only issues I have noticed is lighting at bedrock level near lava in the overworld is broken. It reports as 15 light level, even when the lava is behind a wall of blocks.

thanks for the reply Georgii i appreciate knowing that you are trying to fix this. the question i have now though is, if you cant find an exact cause for this then does that mean people with this problem, updating a 1.13.2 world, will have to start fresh worlds on 1.14?

Nope, someone stated this affects worlds created in 1.14 too.
https://bugs.mojang.com/browse/MC-142134?focusedCommentId=54047#comment-540478

I'm on a server and we started fresh in 1.14 so starting from a new world in 1.14 doesn't help. Our server admin has eraseCache as part of the server restart script and our server is set to reset nightly. It still happens. I did notice that if I travel to my base by the nether, it was mostly fine. But the other day when I was crossing the portal multiple times within about half an hour (I was working just on the other side of the portal in the nether and constantly needed more blocks), I was able to trigger the lighting issue, and then died to 3 baby zombies in my dark storage room.

We just updated to the 1.14.1 pre-release. In coming back through to my base from the portal, I did see that the lighting issue was still in full effect in the mining tunnels (y=11). In the big room where I had placed and replaced torches a couple of days ago, light values were still a little messed up. For example, a block where I had a torch told me it had a light level of 9 or 10, not quite mob spawning, but not what I was expecting for a torch on a block. When I went up to the storage room (y level around the 50s and right above the dark area), storage room was fine with appropriate light levels.

It isn't fixed in the 1.14.1 pre-1 snapshot. Still happens, and areas of the world that were darkened due to the bug are still darkened once you update the world to 1.14.1 pre-1 snapshot.

Unproven Theory: I believe this may be related to slime chunks. On my server, several players have the same chunk(s) going dark when they get this bug, and it seems it is their slime chunks. Not to also mention, I really haven't noticed any slimes in my mine tunnels, which I normally see them often, because I dig them 3x3 and turn them into vine farms.

That is extremely interesting regarding the slime chunks. I just made a slime farm on my 1.14 vanilla server and almost every torch light was bugged out when I restarted and logged back in.

I went back onto my server and did a survey of my slime chunks with regards to torches going out. Unfortunately, test inconclusive - there were chunks with torches out that were NOT slime chunks.

After seeing the post about slime chunks, I decided to take a walk around my base with a slime chunk finder open and there does seem to be some correlation between the two. My slime farm is also pitch black. It's also worth noting that this bug doesn't appear in the nether, as far as I can tell, and since there are only slime chunks in the overworld this could be the culprit.

I too am very disappointed that the 1.14.1 pre-release has no mention of the lighting bug. Even though I can sympathize with the issue that the bug is difficult to reproduce on demand - my own attempts at reproducing it on new worlds has not met with success - the bug itself is happening rather too often in my main world for me to be appreciative of efforts that are yet fruitless.

having read about the slime chunk theroy i decided to check that in our world and although it has affected slime chunks it has also affected non-slime chunks. though it does seem to be close to slime chunks if that means anything.

I can confirm the bug is not limited to slime chunks. I have a hole under ground about 11 blocks high and 201x201 blocks in size, and at one point with this bug all but about a small handful were affected and I was able to confirm that the whole hole is not covered by slime chunks. It does however appear to be more linked with chunk unloading and then reloading which would explain why people notice it more when portal hopping.

I have not noticed any correlation with slime chunks either. However I have noticed that when it occurs it always seems to occur upon login on a multiplayer server.

This comment noticed the same thing: https://bugs.mojang.com/browse/MC-142134?focusedCommentId=541020&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-541020

English is not my native language so bear with me!

This bug happened to me in my minecraft realms twice, I manage to reinstall most light source after 1st bug but then it appeared again today.

At the 2nd time I can confirm that it happened when Im logging in with 1 other player already online, unfortunately I dont remember if my friend online at the first time.

I also want to add that my friend is far away from my position when im log in and log out, I dont know the exact range but definately outside my chunk load.

Hope this helps, will update later if I found anything worth mention!

This bug was occurring regularly in my Realms world at my underground base when I signed in or returned from the nether.  I tried adjusting my render distance from 10 to 12 yesterday and it has not happened since.  It did not fix the lights that had already been placed, but the bug has not occurred again after replacing the lights.

Perhaps a user using render distance 10 triggers the bug when the overworld is loaded, and the other users see the bug due to caching?

Also, I only have three slime chunks out of 16 in my base, but almost all of the chunks are affected.

This bug seemed to happen when rendering a new chunk region. Mainly when either joining the server or exiting the nether.

An instance of the bug keeps ocurring to me on a multiplayer server, where I am afk fishing in a spot, not moving, and people come and leave the server, and the chunk I am in gets dark when I come back to check on my game.

Only skylight works on these chunks, since that is what probably was fixed on pre release 3

Yesterday we discovered that multiple chunks in the Nether - nearly half of the chunks near 0,0 - have gone dark with this bug. Again, ours is a world that was updated straight from 1.13.2 to 1.14 - and did not experience any of the snapshots. This bug is now reoccurring at too fast a pace for me to just keep fixing it every few days with the "Optimize World" function. Strangely, only the same region of the world, my city project to be precise, seems to be getting this bug with any regularity. The bug that occurred on the Nether is the only one that hasn't occurred in the same area. I can also confirm that the lighting bug is not connected to slime chunks in our case.

Does the "optimize world" function with clear cache turned on have a risk of removing entities? I'm asking because we've just had the second case of all entities disappearing from certain, seemingly random chunks. Horses, armour stands, maps on item frames, paintings. In both cases, the removal was permanent and was discovered shortly after the "optimization" was completed.

From the above few comments, I can also confirm this happens on newly generated 1.14 vanilla server worlds, not just worlds upgraded from 1.13.2

To those who experienced the bug while just standing afk:

• Did the light disappear also in the chunks you were standing in or only in distant chunks?

• Did the light disappear serverside and clientside (check with f3) WHILE standing afk?

• Or did it only disappear clientside after moving around or reloading the world?

• Can you tell if the issue happend roughly at the same time for server and client (check with f3)?

• Were there any nearby (redstone-)contraptions (at any point in time since server restart) that could cause a large number of block updates in a single tick?

• Could you also experience the bug in singleplayer or only on dedicated servers?

• For completeness: Are you close to/in the spawn chunks or far away from those?
   

Can confirm that it happens on 1.14.1 Pre-1, haven't tested pre-2 yet.

well as far as pre-release 2, the notes dont say its fixed plus it still says unresolved on here so im guessing its not fixed. i did however notice this on there pre-release notes, Update: We've now released 1.14.1 pre-release 2 which fixes a few issues. Unless any major show stopper pops up, we aim to release 1.14.1 on Monday, May 13th. I would hope this means it should be fixed this week as i would say this bug is a major show stopper.

It seems to be worse in 1.14.1 pre 2. Hundreds of (maybe thousands of) chunks went dark at the same time, making a whole island into a mob farm! Have never experienced this bug at this scale! 😞

if its worse, then it could be a good thing as they can hopefully see what they changed between releases and maybe narrow down the cause

Upgraded my 1.14 Vanilla Server World to a 1.14.1-pre-2 Single Player World.

Lighting issue still exists after upgrade:

Unfortunately, I have to agree with Gary Cousins. My players on my server are EXTREMELY unhappy with this glitch because they are having things like Iron Golems dying in their slime farms. 

I also think this is a showstopper bug.

I think this is the worst bug of 1.14 (even more than the chunk rendering bug). My vote would be to fix this before 1.14.1 release if possible.

I will do my best to continue to help with this issue as well.

I also just experienced this in 1.14.1 pre 2. I died in a cave and then came back to the chunks where I died from spawn via the nether. Once I got underground everything looked unlit even though I had torches everywhere.  Mobs were spawning all over, even right next to torches since the area was now dark and light source were no longer illuminating the area.

I cancelled my realms due to this bug, which makes the game unplayable for me due to reasons others have already stated. I won't be playing Minecraft until it is fixed unfortunately.

To answer some questions: this happened again on a multiplayer server. 

To those who experienced the bug while just standing afk:

• Did the light disappear also in the chunks you were standing in or only in distant chunks?

One player was on the server afk, not anywhere close to me.  When I joined the server, my whole area was dark.  So it's not a local problem.

• Or did it only disappear clientside after moving around or reloading the world?

It was like that as soon as I logged in

• Were there any nearby (redstone-)contraptions (at any point in time since server restart) that could cause a large number of block updates in a single tick?

A melon farm (with observers and pistons and minecart collection.  Not a huge farm

• Could you also experience the bug in singleplayer or only on dedicated servers?

I've only had it happen on servers.

• For completeness: Are you close to/in the spawn chunks or far away from those?

Very far from spawn.

I run a linux CentOS 7 server on a VPS, i restart my server with --eraseCache and --forceUpgrade, they fix the lighting glitch for a little bit until i go to the nether and come back.

Steps to reproduce:

1. Make a world

2. light up stuff around, caves, etc.

3. Go to the nether for a minute

4. Come back and some chunks are now entirely dark, this is easier seen in spectator mode.

Just something to add: I have a mob spawner farm for skeletons near the surface, i have it made out of glass but covered with cobblestone, skeletons are burning during daylight when light sources are bugged in this chunk, perhaps lighting as a whole is broken in certain chunks when bugged.

Edit: The skeletons do not burn during daytime if the chunks have been "Upgraded", only occurs when the chunks bug again

Edit Replication: 

1: Make a mob farm at a skeleton spawner near the surface out of glass tubes

2: Cover glass tubes in cobblestone at the top

3: Enter nether and leave nether back to spawner until light sources are bugged

4: During daytime, the skeletons should burn when reaching the end of the farm, depsite behind shielded by cobblestone

I had the same problem. Optimizing and clearing cached data fixed it until I left the chunk.

I too concur with this being a showstopper bug. I have not logged into my own Realms server (which was left at 1.13) for fear of this issue causing major issues and have been contemplating cancelling paying for it until it's resolved 😞

In reply to the questions posted earlier:

• Did the light disappear also in the chunks you were standing in or only in distant chunks?
  Chunks I was in and nearby chunks

• Did the light disappear server-side and client-side (check with f3) WHILE standing afk?

• Or did it only disappear client-side after moving around or reloading the world?
  I'm unsure, but I seem to recall it being both and it has happened while AFKing. In every case, I did not see it disappear. Each time, everything was seemingly fine when I disconnected and then discovered to be broken after logging back into the server. And in every case, I was the only person near where I was. Others were on other parts of the server though (> 6000 blocks away) and sometimes travelling back-and-forth to the nether.

• Can you tell if the issue happened roughly at the same time for server and client (check with f3)?
  Unsure, but my assumption is yes based on the fact that I was the only one near the chunks, and the issue was present when I logged back in.

• Were there any nearby (redstone-)contraptions (at any point in time since server restart) that could cause a large number of block updates in a single tick?
  No.  On a small island in the middle of a deep ocean biome with not much of anything yet.

• Could you also experience the bug in singleplayer or only on dedicated servers?
  Only on servers so far, specifically Realms servers.

• For completeness: Are you close to/in the spawn chunks or far away from those?
  Far away. Over 6000 blocks away from spawn and other players.

I have to admit I've been seeing mobs burning inside during day time as well. But interestingly that has been happening in chunks separate from the ones that have gone dark. So I would conclude from that that whilst related in that both are to do with lighting, I would have to say it is different scenario.

Also in one instance I have found that a dark chunk is not dark all the way from the surface down. That is in one case on the server I play on we have a tall building with multiple floors, and only some of the higher floors are affected leaving the ground floor unaffected. But to add to that I would say there doesn't appear to be a vertical limit to how far down a chunk is affected as I have seen a case where the entire chunk from surface to bedrock is affected too.

My entire house went pitch black, even my beacon beam! Why does the pink beacon beam turned black as well! (But you can still see some pink-ish color in the black beam)

On latest snapshot currently (1.14.1 Pre 2), on a server, my base i've found that what triggers the lighting glitch is loading the world via nether portal entrance, if i run away/come back after fixing chunks, it's fine, but after using a nether portal, then coming back through it the light glitches horrifically then in a chunk by chunk basis, always the same chunks, and pertains the glitch until updated, although they will revert on portal exit again.
Hope this helps for recreating it!

I've been trying to reproduce the lighting glitch in single player to help resolve this bug faster and I have been able to reprroduce the problem on singleplayer, however, unreliably. I have taken a number of differnet approaches but after obtaining the lighting glitch a specific way, in a new world that method no longer works to reproduce it. I'm not sure what steps I'm taking to reproduce it fully. However, within 20 minutes of creating a new world I am usually able to reproduce the lighting glitch.

For testing purposes I used:

• Create a new creative world with a superflat customized as follows:

  minecraft:bedrock,60*minecraft:stone,1*minecraft:glowstone,10*minecraft:air,1*minecraft:stone

• When you spawn, dig down through the stone ceiling.

After this, I am uncertain of the exact steps to reproduce the bug but in no specific order I have tried the following and some combination of them seem to reproduce the lighting glitch:

• Create a nether portal at 0,60,0.

• Teleport to 8000,60,8000. Create a nether portal. Don't enter. Teleport back to 0,60,0. Enter the nether portal. Teleport to 1000,60,1000. Create a nether portal in the nether. It will link to the other one. Enter the portal. (Might cause the lighting bug)

• Teleport repeatedly to and from 0,60,0 and 8000,60,8000 (might cause the bug)

• Change render distance to 2 chunks, walk/fly around a bit. Change render distance to max. Fly around. (I may have reproduced it using this method. All chunks in a circle at chunk 15 (the edge of the 32 chunk max render distance) around my nether portal turned dark (even though I changed my render distance while I was nowhere near my nether portal). But, again, I'm uncertain how to reproduce as I've tried in multiple worlds to reproduce using this method and cannot get it reliably. It is always occurring randomly...

• Teleport repeatedly through the nether portal at 8000,60,8000 (10-20 times as fast as the portal will let you.)
  *Teleport repeatedly through the nether portal at 0,60,0 (10-20 times as fast as the portal will let you.) After doing this either: Teleport to 1000,60,1000 in the nether and enter the portal there OR teleport to 8000,60,8000 while in the overworld. (may cause lighting bug)

• Fly 3000 blocks away from the nether portal and fly back. (never seemed to reproduce it but it was something I tried in all my runs)

• Fly away from the portal. While the world is loading you can catch up and be able to stand in a chunk that hasn't loaded. When in an unloaded chunk, hit escape, change your chunk render to 2, and quit the game. Re-enter and change chunk render to max. (might reproduce?)

During my tests which only included the actions listed above, it took maybe 10-20 minutes before I was able to see the lighting glitch occur. You will know the lighting glitch has happened because mobs will start spawning on the glowstone and bats will fly around. (To ensure mobs spawn & mod cap is not reached, do /time set day when it starts to become night)

• Did the light disappear also in the chunks you were standing in or only in distant chunks? Only distant chunks.

• Did the light disappear server-side and client-side (check with f3) WHILE standing afk? Or did it only disappear client-side after moving around or reloading the world? Not sure. It was single player though.

• Can you tell if the issue happened roughly at the same time for server and client (check with f3)? Not sure.

• Were there any nearby (redstone-)contraptions (at any point in time since server restart) that could cause a large number of block updates in a single tick? No redstone anywhere.

• Could you also experience the bug in singleplayer or only on dedicated servers? Singleplayer and multiplayer.

• For completeness: Are you close to/in the spawn chunks or far away from those? Far away.

My computer specs:

• 8x core i7 6700k @ 4GHz

• GeForce GTX 1060

• 4.6.0 NVIDIA 417.35

For people commenting on this thread: This is a bug report not a discussion thread. Don't post to say "I also have this issue" or "I'm super upset, etc.". If you don't have any information to help debug/fix the issue please don't spam the thread. There is more than enough screenshots/votes for them to know

Following Quinn Bast's instructions only took a few minutes...  1.14.1 pre 2

This is after passing through the spawn point nether portal between 5 and 10 times.

• Did the light disappear also in the chunks you were standing in or only in distant chunks? yes, light from nether portal disappeared. was bombarded by ghast immediately after this 1st screenshot so don't have that one.

• Did the light disappear server-side and client-side (check with f3) WHILE standing afk? Or did it only disappear client-side after moving around or reloading the world? single player, not afk. the chunk the portal is in was dark upon loading. (along with all the ones visible around...

• Can you tell if the issue happened roughly at the same time for server and client (check with f3)? Not sure.

• Were there any nearby (redstone-)contraptions (at any point in time since server restart) that could cause a large number of block updates in a single tick? No redstone anywhere.

• Could you also experience the bug in singleplayer or only on dedicated servers? This is single player-did not open to LAN

• For completeness: Are you close to/in the spawn chunks or far away from those? Nether -

This bug happeed again on a server but there was some weird accompanying glitches.  I'm not sure if it's the same bug but it happened at the same time as the lighting glitch.

1) Some random blocks disappeared: farmland, wooden slabs, terra cotta, wooden planks.  See screenshots.

2) Lots of villagers are missing.  Unclear whether they died or are glitched outsomehow.  There's some weird behavior: some of the beds say they are occupied when they are clearly not.  Also the remaining villagers cannot reproduce; they do not think there are extra beds.  See screenshots.

3) Some signs were missing but then reappeared later.

After prohibiting all use of Nether Portals as a temporary measure, I'm pleased to note that there have been no new occurrences of the block light bug in my server. We're still running 1.14 full. As such, I think I can also testify, albeit indirectly, that using the portal is linked to the bug. Perhaps related to the massive lag spike? None of the other methods of travel - including long-distance teleport commands - have yet to cause chunks to go dark. It's been a week since we prohibited the use of portals.

Willian that is very good to know. If I am not mistaken, it was said this bug was fixed in 1.14-pre4. Then, in 1.14pre5 Mojang added NEW nether portal logic, which keeps chunks loaded between nether/overworld for 14 seconds one a player enters/leaves. I wonder if this logic (keeping chunks loaded for 14 seconds) has something to do with the bug?

yeah we had most of our black spots turn up after coming out of nether portals too. i hope this is fixed by tomorrow when they hope to release 1.14.1

The last cause of this issue seems to be correlated with traveling from the Nether. Nether portals are known in 1.14 for causing a massive amount of server lag when finding portal location. MC-117914
May this be in any way affecting the lightning processing.

Is anyone able to reproduce this bug from scratch in 1.14-pre3 or 1.14-pre4? I haven't been able to yet.

Looking at the comments it seems like nobody had issues during these snapshots. 

If this is the case, that pretty much narrows it down to 1.14-pre5 (most likely nether portal optimizations)

Our server experienced the bug in all 1.14 pre-releases hence why we are very annoyed it was allowed to stay in the full release

@unknown, "from scratch" means "in a newly created world". If you haven't reset the world on your server, the bug would have stayed from your world you had previously unless you reset the complete chunk cache.

@unknown, that's an interesting question. Indeed, I cannot find anyone stating that this issue occurred in a new world from 1.14-pre3 or 1.14-pre4.

@unknown, thanks for the experiments! However, I haven't been able to reproduce this that way myself in singleplayer. I think it's quite clear that this is related to chunk loading though.

I also want to remind anyone that this is not a discussion forum. If you don't have anything constructive to add to this ticket, please don't post a comment.

sorry let me rephrase, we experienced the bug in each pre-release using a 1.13.2 world that hadn't been updated with each pre-release, ding the optimized world erased cache trick too.

Ran into this first time today, but it had nothing to do with nether at all. Just logged in and a whole bunch of chunks had killed light.

Friends minecraft realm updated from 1.13 to 1.14 started having this issue. First it was couple times a week (that we know of). Now it happens almost every log in. At best it took 2 hours manually replacing all light sources (with two ppl). Once we tried the recommended fix but it helped for max a day. Not sure if it even caused it to occur more often. Currently the realm is pretty unplayable without having the monster spawning set to false. Hopefully this is fixed soon so that we can have real survival minecraft experience.

But ye for others unenabling the monster spawning might be serious option for the time being.

My world is created in 1.14 pre 1, and I'm using "--forceUpgrade --eraseCache" everytime when I upgrade/redtart my server, but this bug still happens everytime.

As far as I know, this bug is most likely to betrigged when a player logs in or comes out from a nether/end portal, while travelling around seems to have nothing to do with this. What's more, the chunks going dark are always the same chunks, no matter how many times I erase the cache or restart the server. And the scale of this bug in 1.14.1 pre 2 seem to be way larger than what it was before 1.14.1 pre 2, with hundreds of  continuous chunks went dark at the same time.

This happens to me on a multiplayer server randomly. The map started in 1.13.2 and has been updated to 1.14 and then again to 1.14.1 pre-release 2. The cache got erased when upgrading from 1.13 to 1.14.

Currently on a survival Realm that is older than 1.13 (don't recall what version it began in) which was (somewhat) recently updated to the full release 1.14.  The bug has been happening about once a week on the weekend.  It's somewhat disturbing this bug is still present from pre-release versions back in January, as it makes this Realm unplayable due to the vast areas of light sources going dark.

My experience is just like all of yours, with the exception that this bug hasn't happened since we lowered the server view distance from 16 to 10.

One world that was created a 1.14 snapshot and one world that was created in 1.13.2 and upgraded – both of which has no issues with the lighting bug anymore.

It would be interesting to see if people can report their server view distance and find some correlation... maybe?

Yes, the less view distance is, the less lag and the less chunks affected by lightnning. This glitch seems very influenced by lag. Usually playing with view distance of 8, and I've only had this issue once (although can't confirm for pre releases, it was in 1.14). Actually  happened the only time when the lag is always consistent for me, which is using Nether portals.

This bug still persist on my server even the render distance is 10. Here are my server settings not sure if it will help. Can constantly recreate the problem by restarting the server.

spawn-protection=0
max-tick-time=60000
query.port=25565
generator-settings=
force-gamemode=false
allow-nether=true
enforce-whitelist=false
gamemode=survival
broadcast-console-to-ops=true
enable-query=false
player-idle-timeout=0
difficulty=hard
spawn-monsters=true
broadcast-rcon-to-ops=true
op-permission-level=4
pvp=true
snooper-enabled=true
level-type=default
hardcore=false
enable-command-block=true
max-players=20
network-compression-threshold=256
resource-pack-sha1=
max-world-size=29999984
rcon.port=25575
server-port=25564
server-ip=
spawn-npcs=true
allow-flight=true
level-name=world
view-distance=10
resource-pack=
spawn-animals=true
white-list=true
rcon.password=
generate-structures=true
online-mode=true
max-build-height=256
level-seed=-293324826722673
use-native-transport=true
prevent-proxy-connections=false
motd=\u00A7a--\=\=\= [ \u00A76SKADOOSH\!\u00A7r \u00A7a] \=\=\=--\u00A7r\nFun crafting
enable-rcon=false

1.14.1 is out, no mention of a fix (which is ridiculous considering they said it wouldn't release if theres a show stopping bug, which this is) any confirmation on if it is still occurring or not? hopefully it isnt cos i cant see them updating to 1.14.2 for a few months.

Since you only speculate, I can also speculate. They mention 1.14.2 being upcoming, so probably that will be for this bug. 1.14.1 was with main focus for the lag issue.

Agreed - the server is unusable with this lighting issue. Our group has been ignoring the server for a week now waiting on the 1.14.1 to fix this issue. We thought it would be. So, now we're stuck. The clearing the cache stuff doesn't do anything for us.

For dev, here is my plan of action on my server:

1. Pull my 1.14 server world files (world was generated in 1.14)

2. Run clear-cache work-around using 1.14.1 as single-player world

3. Re-upload world files to server, run with 1.14.1 server .jar

I will report back if I am still experiencing lighting issues.

It doesn't have to be a proper fix to make this playable again. Rather than seek to prevent the error, seek to detect the error. Occasionally scan the loaded chunks for a light source with zero output, then refresh the chunk's lighting cache if it is. Based on the symptoms, you might be able to even do this scan just once whenever the chunk is first reloaded (and after sleeping in a bed if that doesn't reload the chunks). I also don't think you have to check every light. In my experience, if it happens for one light, it happens for every light in the chunk. That should make the scan relatively efficient to do. This would also give you a hook to add some logging around when it occurs, which should make it easier to determine the root cause.

I'd much rather have slightly slower chunk loading and/or lights briefly blinking out than going out permanently.

I can confirm the bug is STILL present in 1.14.1

Bug still present in 1.14.1. A different set of chunks breaks on each server reboot, isn't just client side as the lighting stays identical after relog and mobs do spawn in the "unlit" areas. The only way to correct this that I have found is to break every source of light and replace, as even causing a block update does not fix it.

Also reloading my world in a 1.14.1 server caused new light issues, it did not just retain the old ones.

A couple of thoughts:

1. Would it be possible for someone to send you a copy of an affected world since you can't replicate it?

2. Since it seems to be tied to lag and loading/unloading chunks, could the problem lie with the specs of the machines we're running the game on? Maybe the Mojang dev machines are too powerful for the bugs to trigger.

1. Would it be possible for someone to send you a copy of an affected world since you can't replicate it?

Yes, that would be very helpful. Please zip the world file and upload it to a cloud service of your choice (Dropbox, Google Drive, OneDrive, ...) and then link to it here.

2. Since it seems to be tied to lag and loading/unloading chunks, could the problem lie with the specs of the machines we're running the game on? Maybe the Mojang dev machines are too powerful for the bugs to trigger.

Though this is just an uneducated guess from my part, I think the fact that the devs couldn't reproduce this as easily is because all of you seem to experience this issue on servers only... so maybe it has something to do with multiple players in the same world and chunks being loaded / unloaded all the time? I don't think that lag plays a large role, although I can't really disprove that either.

the specs idea is interesting, as it would explain why some people get it and some dont, or maybe server settings are different to single player? i can say from experience though that when ive tried it on our sever it was only me on at that time so the only chunks loading/loaded would be the ones im in and spawn chunks if that helps at all.

doubt it is specs, I've gotten it both on a GTX970 desktop rig and an integrated card. The lighting bugs also sync between all clients on a server and mobs spawn in the incorrectly lit areas.

If it's the system specs, it's the system specs of the server, and not those of the client.

I do not think it is the PC specs, we are experiencing the same issues and they seem to be syncing across everyone on the server. This ranges from quite top-end, new machines to work desktops/laptops without any 3rd party graphics cards.

EDIT: Not sure of full server specs, but we are running on a 6Gig RAM virtual hosted server hosted by GameServers, with only up to around 5 people online concurrently at maximum.

World backup: https://www.dropbox.com/s/zw39ogah5dit6zh/world.zip?dl=0

I haven't done extensive testing, but I think a the below points are correct:

• The fix of clearing the cache works, but is not a permanent fix, the problems reappear after a period.

• The area around spawn does not seem to have the issue at any stage, I am guessing because the chunks do not load/unload constantly?

• My (underground) base area (41,95,-280 in the above world backup), away from spawn , is where I am noticing the problem. 

  • If I log out for longer than approximately 5 minutes while in the base, when I log in it seems the entire base gets affected by the lighting glitch about half the time (seems random but I have not been monitoring closely).

  • If I log out while at spawn, even for long periods, and then fly to my base on logging in, it seems to not be affected (if it was working on logout).

  • Once a chunk is affected it seems to be affected until I reset the lighting by placing/breaking a torch. This "semi" resets the lighting in a 6-10 block radius (some of the blocks still seem slightly underlit until I place a torch). 

  • If I place a torch in an affected area next to crops, the crops break when the torch is placed.

  • The blocks are definitely reading as light=0, it does not seem to be just a render issue.

  • The server light field is not showing any value, except for the block and sky lights shown in parentheses, not sure if this is normal behavior.

• I believe (although again I have not specifically tested) that if someone else has been on the server between me logging off and back on, that there is a higher chance of the bug materializing in my base when I log in.

Hope this info helps. 🙂

I have to take the opposite opinion on this one. I do not believe this is specs related, and I have two reasons for why I believe this to be the case.

First of all: we are operating on a server since the early February snapshots with 8 gigs of RAM applied to the Minecraft server, a 7700k, and a NVMe SSD. I've been clearing the cache on server load daily. That should be more than enough horsepower to keep up.

Second reason: the lighting glitch does not happen to all areas of the server. It seems to hit specific areas frequently, and not touch other areas at all. Even more weird, as the snapshots went along into the full release, different areas of the map would be hit consistently. For example, a friend of mine would have his area hit with the lighting glitch on a daily basis in February, but then in March/April snapshots, it was my area that was being hit daily while his was not getting hit very often. Since the 1.14 release, my area has yet to be hit by the lighting glitch while three people on our server have been hit with them repeatedly.

As others have stated, I can also confirm that our Spawn area is safe.

Could this have something to do with what is in the chunks or perhaps what is in the chunks in the immediate vicinity? I have seen a small but inconsistent trend where players who have lot's of chests, item frames, rails & carts, or redstone are getting hit harder than others.

My second observation is areas where players are coming and going frequently seem to get hit harder than areas where a player tends to stay and build in a confined area by themselves.

If it is related to specs, this is a massive problem because so many have reported the issue on Realms.  Each time this has happened in my world, it was in a location several thousand blocks from spawn near after exiting a nether portal.  I had a villager breeder in one area and a guardian farm in the other, so potentially lots of entities loaded.

This happened to me randomly in caves at first. But it has happened now when loading chunks after coming through a portal to my base, and also when logging in to the server. It blacks out every floor of my house, my slime farm underground, half of my yard, and half of the nearest village. As well as several other random spots. Torches and jack-o-lanterns can usually be fixed by updating with a torch and breaking it after, but all the lanterns in my house cannot be updated with torches. I have to break and re-place every single lantern. I agree with everyone else on here, it's pretty much un-playable until this is resolved. Unless you want to spend hours redoing all your lighting every other time you load those chunks.

The problems I've had with this on the Realm I play on is not heavily trafficked and there's very little portal usage.  Of the four players who played when the Realm was created, I'm the only one who still actively plays.  The area I've been working on does not require me to regularly travel through portals, but I am thousands of blocks away from spawn (approximately -3000/__ / 7000).  I currently see the problem occur about once a week right when I try to load the game for the first time of the day, and it only affects the areas within my loading area.  It's possible this low amount of activity is why I don't see it occur more often.

I might have found a way to reproduce the bug in 1.14.1.
 
1. Create a superflat world in peaceful difficulty, turn off mob spawning, daylight cycle and then set the time to 20000.
2. Set your render distance to 11.
3. Stand on the ground and issue the command /fill ~50 ~ ~50 ~100 ~ ~100 torch
4. Observe the borders of the square of torches. There should be some irregular lighting patterns: some torches will give off a lighting on a circular radius as expected, but some or most of the lighting will be cut off abruptly in the shape of a rectangle. Stand on the illuminated side of said rectangle and compare the light level to the outside, there should be an abrupt variation. This means the torches are not giving out light like they should.
 
Notes:
i) If this doesn't reproduce the issue on the first try, try teleporting yourself 10000 blocks away or so
ii) I do not know whether steps 1 and 2 are necessary, I just included them because my process succeeded with the settings described
iii) If you get the "That position is not loaded" error message, take a few steps towards positive X and positive Z

Here's a copy of the world on my server, as mentioned:

https://drive.google.com/file/d/18-2aUXXTdsBh57Z1z9xzmiDd2Mn-tavE/view?usp=sharing

There are a lot of lighting errors in the walled town at -240, -2300.

@Tudur Emir Burrell: That's a nice procedure!  It works a lot of the time.  But – I noticed that if I teleport away and come back, it sometimes fixes the bug.  Also, pressing F3, it seems that there is a discrepancy between the server and client lighting (singleplayer).  The bug described here, as I tend to encounter it on multiplayer servers, usually has both server and client with the same bug.  Do you have the same experience?

@Harrison I haven't experienced this in singleplayer survival yet, but I have in multiplayer, mainly when visiting some of my friends' bases.

In one of them, light stopped working on a regular basis and an army of mobs would spawn inside while he was away. Also, torches in mines would frequently be off.

In another base, the edges of chunk borders had torches that would not light up adjacent chunks with no light sources.

By the way, when testing my procedure on my 1.14 (not 1.14.1) server, the light level would be broken for the server and for the client – 0 in both cases.

Apart from servers, this seems to be also happening in single player world, a famous one actually, which is the 10 years anniversary map.

But only one chunk goes dark after I quit and reopened the world, and I'm not sure why there is only half of it being completely dark...

Version 1.14.1 release.

Can confirm this is still present in the 1.14.1 Java edition while playing singleplayer. Coming from the nether to the overworld triggers it sometimes. I also saw it when returning from the End - I have a bed near my end portal and had slept there because a prior trip to the end had ended up with an end gateway murdering me (separate bug). When I returned from the end the second time, the area was dark again (it had also glitched before coming there from my nearby nether portal - I had fixed some of the nearby lighting issues so I was startled to see it dark again).

Can confirm still happening on 1.14.1. A member of my server sent this screenshot today after 1.14.1 upgrade from 1.14 with --forceUpgrade --eraseCache:

EDIT: If needed be, let me know and I can provide a link to download my server's world for testing purposes.

i wonder if this is somehow connected to MC-151082, https://bugs.mojang.com/projects/MC/issues/MC-151082?filter=allopenissues
reading the comments there it seems server lag and tick rates get progressively worse and happens more when moving a good distance which sounds kinda familiar

I have done the following on my server (my server was generated in 1.14 vanilla release)

1. Pulled my servers world files
2. Ran the workaround mentioned above in the 1.14.1 launcher, single player world method (this also upgraded world from 1.14 to 1.14.1)
3. Pushed world files to server
4. Ran server with 1.14.1 jar in multicraft (Apex hosting)

My result is that we are still experiencing the lighting bug but it seems to be a on a much lesser scale than as before on 1.14, or at least the torches are going out at a slower pace.

Simultaneously, the amount of lag we experience now (after updating to 1.14.1) seems dramatically reduced on the server.

This leads me to believe that this issue is lag related on a server. I think people were correlating this bug to nether portals, because nether portals always produce a huge lag spike.

 I can confirm this in 1.14.1. See 2019-05-14_18.35.09.png

World was created brand new in vanilla 1.14 on April 26th. 

I also agree that the issue is not related to specs, if Realms servers are experiencing this problem then it should not be a spec related issue. 

This could also be related to servers taking up massive amounts of CPU and memory even with 0 players online, it could be generating lag and issues itself.

Definitely not a specs issue, my server is running on a 7700k dedicated to that server and nothing else. 

For my world, everything has been fine from 1.14 release until today, where a bunch of chunks around the world got hit at once. I have a copy of the world with the glitch still present if a link to a download is helpful. 

Keeps randomly happening, can't replicate the issue.  Areas with lots of traffic just lose their lighting, areas with no use at all for days that are returned to lose their lighting.  It seems server driven, not player driven to us.  It does seem to happen to multiple chunks at one-time though but beyond that nothing in common we can find as it happens on new servers and updated servers.  

Is there a way of erasing the cache directly from the files, rather than having to use the optimise world function?

(See the Moderator Notice on how to fix this bug)

Yes, theoretically you can edit all the NBT files and erase the cached light data from them, however I would not recommend doing that as it might easily corrupt your world file and the optimize world feature does pretty much the same.

From what I can tell, the optimize world function also doesn't always solve the issue. The easiest way to resolve the problem is to replace every light source in the affected chunk(s). The moderator notice on top was put there because the bug was supposed to be fixed in 1.14-pre3, but older worlds would still have the issue.

does replacing all the lights actually stop it happening again?

Probably not. There's no permanent fix that we know of.

Random side thought - Do chunks load differently in spectator mode? I tend to see the glitch happen more often when I load chunks in spectator mode, although it could just be coincidence.

ah ok, thank you.

just noticed this bug is 4 months old now lol

I just ran into this and I thought it would be significant. This is the first time I have seen the lighting glitch in the nether. Running 1.14.1 vanilla server:

hey guys i just been looking in to spigot for 1.14 (though its not released yet) and came across this, https://hub.spigotmc.org/jira/browse/SPIGOT-4884?filter=-9
it seems they have fixed the problem so maybe the people dealing with the bug may want to get in touch with them to find out how they fixed it.

The Realm I am on has this issue even after 1.14.1. It does not yet appear to affect spawn, just areas that get unloaded. Should this be reported separately as a Realm bug or are both being worked on?

tried the latest spigot and it took alot longer than normal but then the dark patches came back ;(

@garycousins I would recommend reporting it on the bug tracker link for Spigot you posted earlier, since md_5 isn't going to check this page for bugs also included in Spigot. 

SPIGOT-4884 was resolved as "Done", not "Fixed". The reporter of that ticket reported that the issue no longer occurred for him, and hence the ticket was closed. No actions have been taken by the Spigot team to fix the bug.

@violine1101 is there any news on your progress with this bug? It's really ruining the server I play on. If it helps I can send the world files of an affected world.

Thats a shame, i was so hoping someone would have a fix, 4 months and still no closer to a fix.

As I'm not a Mojang employee, I don't know the exact status of this bug.

However, Mojang are aware of it. They have stated that they are currently working on it, and are planning for a 1.14.2.

Unfortunately this issue is not easily reproducible and hence it doesn't seem to be easy to find the cause of this issue. So, don't expect the issue to be fixed too soon. (Especially with Minecraft's 10 year anniversary coming up, the devs will probably be pretty busy this week anyways.)

For me it seems to be reoccuring if i go into the nether and back. So i clear the cache, everything is fine, then i go to the nether and come back, the areas are affected again. Happens 90% of the time.

FWIW the steps given in the Spigot bug don't reproduce the bug in vanilla either.

This is happening many times a day now, and I have downloaded the realm world to Single Player and re-Uploaded it many times this week. This fixes the issue anywhere from days to only hours. We are all getting really bummed out that this keeps ruining our server experience. Do we have any updates on this bug, or is there anything else we can all do to help figure out what is causing this issue? I do not need to post a screenshot as those that are already submitted show what is happening.

Edit: To add on to this, This occurs without any of us entering the Nether. I want to add that we have been messing with /time commands and wonder if this is doing it. Other things that we do are hopping to and from spectate or creative/survival often. Otherwise, this happens with Resource texture packs on or Vanilla, but on a realms server (no Mods).

I'm not sure I agree about the "not easily reproducible" part. I have the problem with same chunks over and over 100% of the time (see light sources aren't working across entire chunk, destroy them all and replace, now they work, unload the chunk, reload the chunk, every light source in the same chunk has again stopped working), so filling a terrain with any light source and looking for the black spots ought to work on any seed. Mojang knew about it pre-release, and they knew about it after 1.14 came out, so I was surprised 1.14.1 didn't fix it since lighting is a fundamental aspect of the game. I appreciate and admire the technical skill it takes to track this stuff down, but it's a little hard to understand how the error can survive two intense development cycles.

could the devs not join someones world that it affects, or someones world where its easily reproduced? maybe then they can get the info they need? also thanks for the update violine1101, im sure they are working on it and hope they will fix it soon, but i think we can all agree that 1.14 shouldn't of been released in the first place with such a bad bug.

another thought, could the devs whip us up a version of 1.14 that DOESNT have the new lighting engine? not saying that its the cause but we could at least rule it out.

Hi team, I have the same problem of Ryan with my realm, same steps. The workaround fixes the issue anywhere from days to only hours, the 1.14.1 didn't change anything. We don't use console command and doesn't change game mode.

My realm's players are getting really annoyed by this and we could soon leave the subscription since it's not acceptable to download-clear-reload 1-2 times at day, with the risk of ruining most of our work.

Attached are some screenshots showing affected chunks over time, those are created with Mapcrafter (which uses the lightning and heightmap for map generation).

Notable changes to those chunks happenend under the following circumstances:

• Leaving the area via nether portal

• Entering the area via nether portal

• Disconnecting from the server whilst in the area

If you want the world download, it can be found here https://mc.poebel.net/backups/

Initial state, player online and working in the area where the creeper/player icon is.

After leaving the area through the nether portal

After re-entering the area through the same nether portal

After disconnecting

its fixed? 1.14.2 pre 1 says it is. if it is in fact fixed i would love to know what the cause was.

If this is still happening to you, and if you have a backup of the world right before you can trigger the issue, that might help; I managed to get one and consistently reproduce it, and fixed what was causing it, but there might be more to it; if you can reproduce it by

1. Restoring the backup

2. Choosing edit -> optimize -> erase cached data (before loading it)

3. See the issue immediately after loading the world

Then it would be very helpful if you can share your world backup, along with what render distance you're using.

Thanks!

I'm sorry, Georgii - this was PEBKAC all the way. I've deleted my previous comment, thank you for your time.

No worries, better safe then sorry 😉

This is still happening on my server even after world optimization and erasing the cache on single player and have also tried with the batch file commands as well right on server startup. This has been marked as fixed but does not seem to be. I hope that the bug can be fixed without the need to restart our server world that has hundreds of hours of work on it.

World was originally created on the 1.14 release version and have tried erasing cache and optimizing multiple times on each update including 1.14.2 pre 1

I have received confirmation from players on our server that this bug still exists in Snapshot 1.14.2 Pre-release 1.

thats a shame, i really hoped it was sorted out. i could give a download of our world if it helps but i dont know what triggers the bug, as sometimes it takes some time before the bug appears so i wouldnt be able to provide a download of just befor it happens, and i dont really want to update to 1.14.2 pre 1 to test it if theres people saying its not fixed as our server members are already very annoyed from all this going back and forth.

OK spoke too soon, this is still happening in 1.14.2 pre-2. I'll attach a backup of the world before I did a forceUpgrade and eraseCache. I can easily reproduce at will by:

1. Start server with --forceUpgrade --eraseCache

2. Going to my underground base at -303, 80, 406. You will see lighting looks normal.

3. Logout and wait for 5 mins.

4. Log back in. Lighting is broken again.

Here is how it looks like:

Here is the backup zip of the world: 

https://drive.google.com/open?id=1QbSSvCYDAiK0jdATsFk_hOI8P80xQOV8

I hope this helps everyone to nailing the fix for this very annoying bug.

i was really hoping to celebrate minecrafts 10 yr birthday in 1.14 too. oh well better reopen the bug i guess its a shame we cant get a refund of our time wasted with this bug.

I just read that 1.14.2 is expected to release next week. Please fix this before the release! There's so much hype about the 10 year anniversary but we haven't even had a playable release for 1.14 yet because of this bug, which (for some reason) has not yet been re-opened?

I can confirm this bug is still present in 1.14.2 pre1. 

@Christopher Fry i hope its done for 1.14.2 too but its become evidently apparent that the minecraft higher ups don't have a problem releasing full updates with 4 months old game breaking bugs and though i'm sure the guys working to fix this bug are working hard to find a fix i wouldn't get your hopes up, all the people on our server did, especially the times it was supposedly fixed, only for them to be dashed with every release.

I'm playing in 1.14.2 Pre-Release 2 - The lighting issue is still present. We reloaded the new server. Ran the command line to clean the cache. Everything looked fine, then after 1 night, the lighting issue returned. It's still that way now.

Ok, so I have been wandering around the server I run and have noticed that there are only a few chunk load/unload conditions that have caused dark chunks.

So far the only conditions I have found are chunks unloading as a result of disconnect or going through a nether portal.

Chunks loading from connection, portal or coming into draw distance, as well as chunks unloading for leaving draw distance haven't produced any dark chunks that I have been able to notice.

However that doesn't rule out the conditions I didn't experience dark chunks from.

I keep reading that this is resolved on all the snapshots to date released but I am still getting this painful bug on my server

I play on a realms server that is managed by someone who doesn't play very much and I've had to quit Minecraft completely. Hours upon hours of work have been ruined due to creepers and zombies spawning on top of well-lit areas and ruining my work or killing my villagers. Really hoping this is fixed ASAP. 

https://imgur.com/a/uc75swe

One of many images of my broken world. 

Something I just remembered- hope this is seen by a developer. I was actually traveling back and forth from the nether (which as you might know loads extremely slow) but also the first time I enter the nether each session my game will crash and boot me out of my realm without fail. I remember specifically one time as I zoned back into my world through the nether portal in my picture above, all the lighting was broken - about 2 minutes after seeing it all working. 

Hope this helps, happy to provide more info. 

Reopened.

@unknown, this is a bug tracker and not a discussion forum. If you don't have anything constructive to add to the report, please don't comment here. Consider this a warning.

To anyone who is experiencing this bug in 1.14.2-pre2 after having optimized the world with erasing the cache: If you want to help us with solving this issue for good, please read this comment by @unknown (that's the same comment as in the "Please read" box above). Just commenting "I have this issue as well" is not helpful.

i have noticed few thing that may make it more likely to have this bug more frequent

1)it happens when chunks are loaded and unloaded

2)server need to be lagging to get more chance of this bug

3)more players loading and unloading chunks

4)this bug did not happen is single player so far

Still an issue in 1.14.2 pre release 2. I force upgraded and erased cache, that did fix everything until i re-logged then everything went back to darkness. As reported, if you update the light source it will function normally, it will even stay lit after re-logging for a while but still ultimately goes back to darkness eventually. 

My main base is in complete darkness but other buildings in other areas of the world were unaffected and lit normally. The main base is a large tree, both the exterior of the tree (under the leaf canopy) and all floors of the interior including underground are in complete darkness. I've had the issue is 1.14, 1.14.1 pre release, 1.14.1, and 1.14.2 pre release 2. At no point did it go away. 

This bug was also highlighted in Cubfan85's latest Hermitcraft episode with the automated berry farm. 

My render distance is 16. I'll try to get you a world backup as well.  EDIT: Tried uploading backup but the file is too big. Let me know how to get it to you and I'll share. 

To share world files with us that are too large to be uploaded to the bug tracker directly, please use a third-party cloud service (such as Dropbox, Google Drive, OneDrive, Mediafire, etc.) to upload the video, and then share a link to that file here.

Here is the back up of my world in 1.14.2 pre release 2. 

https://www.dropbox.com/s/0cgmk6rwr2rx0z7/archive-1558272904991.zip?dl=0

The coordinates of the most effected area are x2110, y80, z11333

Some comments after reading through other posts: It is not related to multiple players being on a server. I am on a multiplayer server and there has not been any other players on other than me since I upgraded to 1.14 and encountered this bug. 

To reiterate what I said previously, force upgrading and erasing cache only works until the chunks are unloaded and reloaded, then darkness.  

It is clearly not a hardware issue. Professional MC'ers are having this issue as well. 

It has never been fixed in any version of 1.14 since the full release. I didn't try any 1.14 snapshots so I can't speak on anything before the full release. 

Updating light sources is also just a temporary fix, although it seems to stick longer than doing the force upgrade/erase cache. I've done the force upgrade twice and both times it was completely undone on my next log in. 

It is unrelated to slime chunks, I have a slime farm that covers 4 chunks with no such issue. The chunks I am having the issue with are not slime chunks. 

You guys work hard and everything you do is greatly appreciated. That being said, this is game-breaking and deserves Mojang's complete and undivided attention. Especially since the entity-disappearing bug seems to be fixed, there is no other bug more damaging than this one. 

For me, playing singleplayer, the bug seems to be fixed. Since the update to 1.14.2 pre release 2, I have yet to see it occur again.

I see this issue on Minecraft 1.14.2-pre2. My server is a VPS with openjdk version 1.8.0_171. My client is using render distance 20. I have been unable to find an exact method which reliably produces the bug, but here is what I know:

• EDIT: The bug always seems to affect the same chunks.

• Connecting and disconnecting enough times will cause the bug to occur. No other player actions are necessary. The bug appears to be especially likely to occur if you disconnect, wait for the chunk to unload, and then reconnect.

• Running the "--forceUpgrade --eraseCache" will fix the problem temporarily, but it will be back.

• We have a large world: 2.3 GB. I have attempted to downsize it by keeping only the .mca files which contain buggy chunks. As far as I can tell, the bug does not occur on the downsized world.

• Mapcrafter's "nightlight" render mode shows dark chunks all over the place, including places where the bug occurs. See screenshot.

  • Mapcrafter has not yet been updated for full 1.14 compatibility, so I am not sure what this indicates.

  • It is not necessary to run mapcrafter in order for the bug to occur

I have attached two versions of an .mca file which contains buggy chunks. One version contains the lighting bug, and the other does not. Some block coordinates within an affected chunk are X=96, Z=3108.

Every time I log in, all of the torches in my village have gone nearly dark. They're light-level 0 even in their own block! Monsters are spawning everywhere! This is new since 1.14.1. It did not happen in 1.14.0, so it's not the same bug as earlier (though it might be some kind of regression).

 Loss of light makes villages nearly unplayable. Creative-mode time-add is my only workaround. This bug is just one level less than a drop-dead crash bug.

I hope that this time if it will be the right one.

Re: Yesterday's Darkness

 The owner of the affected server did some kind of cache optimization / flush and then restarted. It seems to be OK now, at least in the dim village where I'm still working. When I move on to my next village (fenced in 1.13.2, needing work tables, bell etc a la 1.14.1), I'll see if the cache cleaning kept the lights on somewhere that I haven't visited recently.

UPDATE: After logging out overnight, the torches and one jack o'lantern had gone dark again, so I spent my first half hour or so breaking and replanting a hundred torches while fighting zombies and skeletons every night (entertaining once, but not how I want to spend my time every visit). On the "bright" side, gossipy villagers spawned 7 golems in under an hour! Oddly, when I went to my next village (first visit since upgrade to 1.14), the lights were on properly. Go figure – maybe it'll choose tonight to go dark. I'm eagerly awaiting 1.14.2 but willing to be patient to get it right.

I see it's marked as being fixed. Maybe it hasn't been implemented yet but I just force upgraded/erased cache again, lighting bug was fixed as per usual, re-logged after letting chunks unload and the bug was back. Complete darkness. Apologies if the fix hasn't been implemented. Thanks for the effort in getting this fixed. 

There has been a fix in 1.14.2 Pre-Release 2, and the fix will be refined in 1.14.2 Pre-Release 3, which will probably come tomorrow. 1.14.2 is planned to be released this week.

If it still an issue in 1.14.2 Pre-Release 3 ?

In 1.14.2 Pre-Release 3 still a problem. (Why did I bother telling you guys there are real problems in the snapshots and getting told to basically shut up, because it will be alright!)

Please optimize your world, erase cache, and then check whether the problem persists. Chunks that already are affected won't fix themselves.

Applying the optimize world function is highly suggested. It will remove any light glitch your world may have before updating.

Is there are argument server owners can run to optimize the world? I know the forceupgrade and erasecache. Just wondering about the optimize.

@Robified The Optimize World button and the forceUpgrade startup option do the same thing: they upgrade all chunks in one go.

Otherwise chunks will be upgraded to the latest format as they get loaded - which takes a brief moment but causes a little stutter nonetheless. And you never really know when everything is up to date unless you run around systematically to load all stale chunks. It's therefore better to force the upgrade / optimize the world offline so that your entire world is stored in the latest format and chunks can be loaded straightaway while playing.

Also see What is the Optimize World option?

Still getting some sort of weird lighting issue, at least around water (my mob farm collection system).

Definitely contained in a chunk, similar as before.

Very minor, but still worth mentioning to see if it's related.

DETAILS:

Original World Generation Version: 1.14

-Upgraded to: 1.14.1 then 1.14.2-pre3 (used --forceUpgrade --eraseCache both times)-

Running As: 1.14.2-pre3 SERVER .jar

Server Render distance: 10

I can send a link to my world files PRE-update and POST-update (update to 1.14.2-pre3) upon request.

UPDATE: I haven't seen any more issues in my world besides this one spot, so it's possible this is just kind of a one-off fluke area. I would be more curious to see if anyone else has issues still. Overall, the update seems good. Thank you for your hard work on this issue!

UPDATE: Turns out this issue is actually unrelated to torch lighting bug (see MC-149518). Thank you ModVioline for pointing this out

@Bitzerker I have been having the exact same sort of issue on my world that you're describing and from the screenshots. I was confused for the longest time why this was happening. I have a witch farm with a 40x40 stone roof overhead and underneath the middle of it, the sky light level is not 0, but the maximum light level. 

I did clear the lighting cache when upgrading to pre-3 this morning, and I just logged on and headed to the same spot to take screenshots and it's fixed for me. If the issue comes back, I'll update this post with the screenshots. 

I think this would warrant a separate bug post since this is more of an issue of lighting not updating rather than lighting suddenly not working like this current bug report details. 

@unknown and @unknown, you have a different issue (MC-149518) which has not been fixed yet.

Well in my case, running 1.14.2_Pre-Release_3 server with --forceUpgrade --eraseCache (or --eraseCache alone) just caused the server to hang at "[04:38:26] [Server-Worker-3/INFO]: Preparing spawn area: 0%" at zero cpu usage and no response except hard-killing the java process.

Downgraded to 1.14.2_Pre-Release_2 and it started just fine. However the light seems to be fixed because 1.14.2_Pre-Release_3 upgraded chunks before hanging.

@unknown If you can still reproduce that server hang bug, please report it and if at all possible attach the world file to the report so we can investigate it.

This exact same issue (light sources not working) just started happening within my family's realm's based world yesterday, 5-23-19.   Version 1.14.1 vanilla .  This is for all light sources, not just torches.  It includes naturally occurring sources such as sunlight and lava pools.  This is not just a visual bug, as mobs are spawning in the unexpectedly dark areas. 

I "reset" some of the effected areas by either breaking then replacing sources such as torches.  Also went around with a lava bucket briefly placing lava then picking it back up.   This temporarily reset light sources to function as expected but both after returning from the nether and also quitting // restarting the game the issue returned.    

It makes the game absolutely unplayable in certain areas. 

A couple of examples can be seen in the world at coord's 330/76/1848 & 329/69/1845.

I've never  reported a bug before – so sorry if this is wrong file attached – I spent 15 minutes searching your site for an explanation as to what to attach and no explanation was readily found.  

@unknown or anyone else on Realms or playing on last stable version (1.14.1). This bug has been re-addressed in recent pre-releases, which means the recent patches haven't reached your world yet. If all goes well, your world will be fixed once 1.14.2 is released.

For everyone, as for now, please only post a new comment on this issue if you can reproduce it in the very latest 1.14.2 pre-release 4.

@slicedlime I created this issue about the server hang: MC-152977

Unfortunately, I still had the problem on 1.14.2 pre-release 4, even after using force upgrade and erase cache on the world. Each chunk was fine on first load, but after unloading it and loading it again (done by moving far from the location and then back), the darkness patches were back.

The same thing still happens on 1.14.2 final.

@unknown Unfortunately, knowing that you still have the issue won't be useful if you don't provide more information. Can you provide a copy of you world, especially if you have a backup before triggering the glitch? And if so, from the backup file, do you have a consistent way to reproduce the bug on demand?

Still occurs in the 1.14.2 release.

I'll upload a cut down version of my world, but it's easy to reproduce:
1. Fix the glitch by loading the world with force upgrade and erase cache;
2. Log in, go to the chunk for the first time - it will look fine;

3. Go far away and then back, dark patches will reappear, eg. on the primarine railway station.

And every time the chunk is unloaded and loaded again, the patches increase in quantity.

@unknown, can you please upload a screenshot or two of your issue/the black patches you are talking about?

Can also confirm this is still an issue in 1.14.2. In my case it's a skylight issue. Several subchunks starting from the third topmost down to ground level (or the lowest block perhaps?) the skylight is incorrect; 0 or less than 15 despite there being only air above.

Strangely, ever since the initial fix for this I've never had it in my singleplayer world, however, as soon as I updated to 1.14.2 (from 1.14.2 Pre Release 4) this issue occured. Might be a coincidence though.

I've also attached a screenshot, but here's a video of it in addition since it's hard to properly show in screenshots: https://www.youtube.com/watch?v=cn1D_NYuMIw

@unknown, that sounds like a slightly different issue to me. Please create a new ticket about this.

Edit: MC-153308

Can confirm on 1.14.2. World upgraded from 1.14.1 to 1.14.2 via --forceUpgrade --eraseCache. Not sure when it happened, but I've just today upgraded the chunks and uploaded the world.

As mentioned in this comment, we need to know what your server render distance is, and we need your world backup in order to confirm and solve the issue.

EDIT: Fixed links. Render distance is 10.

Backup - before chunk upgrade from 1.14.1 to 1.14.2: http://craftera.com.br/downloads/worlds/season1/28.05.2019_1.14.2_before_chunk_upgrade.zip

World after chunk upgrade (did this backup just now): http://craftera.com.br/downloads/worlds/season1/29.05.2019_1.14.2_after_chunk_update.zip

Done via --forceUpgrade --eraseCache

Timeline of Events:

So we were playing on 1.14.1 with the usual lighting glitches that were already reported. When 1.14.2 came out I did the backup linked above and swapped the .jar file in the server. Since there was this addition to the 1.14.2, I hoped that I wouldn't need to do the --forceUpgrade --eraseCache command: "All light will now be re-calculated the first time you open a world saved in a pervious version"

So I asked the members of the server to report any issues to me and someone sent me a screenshot of an issue he was having on his mob trap which was related to skylight passing through blocks on his mob-farm: https://media.discordapp.net/attachments/575706169948110858/583008907132272659/JPEG_20190528_160906.jpg?width=481&height=642

Although I was aware of the skylight bug I wasn't following it, so I didn't know if a fix was already proposed. So I figured I should upgrade the chunks to attempt to fix it and whatever other bugs from older chunks we might have. Then we have the second world link, which happened randomly. As other people have mentioned, it seems to be related to dimension change/chunk reloading as I had just left and came back to the Nether and spotted it. The coordinates are in the Nether as in the picture:

X: -203
Y: 74
Z: -64

I did a fly-around and another coordinate caught my attention (the other screenshot I attached):

X: -1374
Y: 100
Z: -244

There's a mob trap in the sky and the pillar made out of cobblestone with the ladders inside is with the light cut off at Y: 95/96 as if the sub-chunk isn't lit? Not sure. This is actually the same chunk as the sky lighting issue the the member reported to me and the one with the screenshot via Discord that I've linked above. The skylight issue was before 1.14.2 chunk upgrade with 1.14.2 jar, and after the issue was this unlit sub-chunk.

People haven't yet reported any other places where this lighting glitch might be occurring and I haven't seen it anywhere else on the server, as of yet, where the lighting is broken. I'll report whatever else I find.