Skylight appearing under blocks

I have had the same issue deep underground in a mob spawner (y=14), making it very difficult to farm mobs (because they either dont spawn, or spontaneously combust because the game thinks they are in the sun). I have found one work-around that always works, but it is time consuming and annoying.  It seems that, whatever causes the bug, it places sources of skylight in a number of air blocks in some random chunk. If you manage to find these blocks (usually anywhere that light due to sky = 15), and fill them with solid blocks, once you break those blocks the issue should be gone. You may have to fill in almost the entire affected region with solid blocks though. This light can also generate in non-full/transparent blocks like slabs, ladders, chests, glass, etc. You will have to break them, replace with a solid block, break the solid block, and then place the original block again to remove the issue. 

I suggest manually filling the brightest part of the underground region with easily breakable solid blocks that you can discern from the rest of the environment. Fill it all up, break the blocks you used to fill, and all should be good. 

Same issue. 

I made a room out of cobblestone, just cobblestone, no slabs or any other blocks make up the room. It has no holes or light sources in it. When I first made the room, it was dark, like it should be, but once I went on the outside of the room and placed torches on the top and around the room, the inside of the room became exposed to a light source. Still no holes anywhere, I went into the room and blocked my entrance hole, and still a very bright light source. Attempted to break the room, and replace all the blocks again, but the "invisible" light source is still present. It is affecting the efficiency of my mob farm, which is the purpose of the room. 

Same issue.

Hope this will be resolved one day :3

Same issue, but under the roof of my witch farm, so my witch farm is crippled, hope this gets fixed soon. 

This is still present in 1.14 (Server) and 1.14.1 Pre-Release 2 (Server), it handicapped my only mobfarm completely, tried filling everything with dirt and removing it solved it for a little while until the chunks get unloaded, when they reload it's back again, extremely frustrating...

Ah-ha! This claimed my zombie villager in my enchanting building.

EDIT: Re-optimizing the world seems to have fixed it whereas blocks changes nor light changes did.

Just ran into the same problem on a server.

Built a zombie grinder at y=11 at it worked really well until my zombies started burning the moment they left water.

An Imgur Album to help

I don't know what caused this or how to replicate it however.

Still in 1.14.1 Release

A quick fix for an above ground mob spawner or affected area is to break and replace every block and I mean EVERY BLOCK

... or an even quicker fix would be to check whether optimizing the world and erasing cache works. A guide for that can be found in MC-142134.

I already tried replacing every single block. Didn’t work 

@Cynthia airblocks are affected too in my case, what I did was just pouring water in the entire room and then draining it and that fixed it for a while.

@violine1101 the quicker fix works, at least in server edition

Still in 1.14.2 Pre-Release 1 and 1.14.2 Pre-Release 2

okay so the two Minecraft tickets one MC-149518 and the other MC-142228 describe lighting issues one where skylight is under opaque blocks essentially and the other no light where light sources are. the issue I am having pertains to both but isn't, I don't think, the same as either. in this case either or both of those issues are recreated instantly after entering the chunk adjacent to the chunk that was previously fixed/and or chunks with a nether portal. so essentially after downloading the server world optimizing and erasing cache on top of running force upgrade erase cache both issues were solved but as soon as I left the adjacent chunk then reentered it used a nether portal both issues reappear as if cache maybe wasn't erased properly, or the nether portal just updates the adjacent chunk in a way that it creates those issues again. this is after moving the portal one chunk out of the original chunk not sure if that has an effect but I don't recall having the issue when the portal was in the same chunk as the light update problems. I hope I made this as clear as possible I don't have images because currently my chunks are fine as I just optimized and am trying to avoid the nether portals and recreating the issue again.

I have same problems with lights, after leaving chunks, unloading them and then came back and reloading them, skylight is bugged. It is same after restarting server or login and log out.

skylight lvl 15 under blocks

I did have a semi useful solution if you literally cover the entire are with blocks like on all six side of the cub it seems to stay dark even after reentering chunks I will say I’m in 1.13.2 pre 3 now but problem still persists

I assume this is the same bug? It happens across chunk borders in my creeper tower.

Looks like it, yes.

This is affecting me in 1.14.3 pre-3. I cleared my lighting cache and that fixed the issue, but it seems to have come back. See the attached screenshots.

Have the asignee determined the source of this bug?, or would more information be helpfull?

I have a witch farm where in 1.14.2 have daylight 15 inside a completely enclosed cobblestone building. Can share world file, or more information.

ps. Crossing my fingers that this fix will make it into 1.14.2

Its fixed 1.14.2 Prerelease 4!!!! Thank you Mojang

Edit: Its broken again, going through the nether and back broke it

It seems like the issue is present even in 1.14.2. There were a few comments about people having the light bugs appearing on different places every time, however on my world it looks as though the chunks being affected are constant. The chunk on the attached image is the one I'm having problems with.

I've tried the erase cache method with success, but the issue reappeared when I slept in a bed. It seems like the source of the bug, at least for me, is when light updates too fast (for example when you sleep in a bed and it turns morning). 

In addition the whole chunk height-wise isn't affected by the bug. For example the basement under the skylighted area (on the picture) isn't affected, even though it's the same chunk.

Hope this helps to find a solution!

Experiencing similar lighting glitch in 1.14.2. Two completely enclosed farms (one witch, one creeper), above ground in the water, and it's as if the blocks aren't there when it comes to lighting. So far my experience has been it being with user created buildings, natural generation doesn't seem effected as of yet (natural spawners still dark, mineshafts and caves, etc.). Will try to clear lighting cache, see if that works for now. Figured I'd just add my voice to the crowd as opposed to opening new ticket, having it closed and moved here anyway :^).

Temporary workaround (fixed it in my case atleast) but you need to be opted in MP or have cheats enabled in SP. So after erasing cache for the world just keep the chunks permanently loaded that are affected with /forceload command.

Went quite a while after upgrading to 1.14.2 with no problems, but now it re-appeared. Same place as before. Inside my witch farm

Happened to mine to and completly broke my witch farm. This needs to be prioritized. Ruins all hostile mob based farms.

Same exact thing happened with me in my witch farm. The border of the chunks is where the skylight comes through in my case. 

Edit: Version 1.14.2

still not fixed in 1.14.3 pre release 1

@unknown Have you tried to do Optimize World -> Erase Cache before updating to 1.14.3-pre1?

Just downloaded my realm and optimized it for 1.14.3-pre1, tested it in single player, seems to be fixed now

My witchfarm doesnt spawn any witches at daytime because skylight goes trough the roof. i have build an roof and encased the farm with solid blocks. when i encased it with solid blocks it seemed to go away but after a couple hours it went back to before. all the blocks below the roof (even the caves) are lit with skylight.

this is an newly created server and has never been updated. im playing on version 1.14.2.

i have added some screenshots that may help.

please fix this problem because its breaks almost all my farms.

Still having this problem in pre-release 2.

Ok in realms server we erased the cache data fixed for a couple 6 hours then the issue re-appeared seems to only be a temporary fix then get reverted to this weird state. I was having this issue with my witch farm roof in which only one of the four chunks that it is in seems to behave properly but the rest are acting in this manner in which light levels are bleeding through the ceiling.

I have this problem, and I optimized my world, in that moment it solves, but, if I enter a nether portal and go back, the problem appears again, and the sky light is 15 again under blocks

This affected a mob farm I built and I found a workaround. Place solid blocks like dirt on the ceiling of the enclosed space and then remove them. This removes the skylight. This may not work in all instances.

This bug is 100% absolutely in no way resolved.

Are you playing in 1.14.3???!