Mod Notice
If your world is still affected by this because you upgraded it from 1.14, please follow the following steps in order to fix your world:
Singleplayer: Select world → Edit world → Optimize world → check "erase cache data" → Backup and load
Multiplayer: Start the server.jar with the following command:
java -jar server.jar --forceUpgrade --eraseCacheThis only needs to be done once, after this you can start your world or the server the usual way again.
Minecraft Realms: Download the world from your realm, copy it into your Minecraft singleplayer worlds folder, follow the steps for singleplayer, and then upload the world back up to your realm.
If the issue occurs again after you've done these steps, please leave a comment.
I was making giant enclosure in the sky for mob spawning so they would path into water and fall enough to almost die. However, I couldn't get it to work as for whatever reason, some blocks saved the light level of the sky during day, re-emitting it. So even at night, mobs don't spawn except in maybe a corner. The issue seems to multiply every time I relog, as I've made effort to fix the issue by replacing blocks, and when I have finally managed to fix it in a section, a relog caused it to come back. This happened with regular blocks, slabs and double half slabs.
As you can see in the screenshots, there was a corner where mobs could theoretically spawn for whatever reason. This was also during the night, so it's not just blocks letting the light through. Hopefully this will be fixed in a way so I don't have to replace so many blocks when a fix rolls around.
Linked issues
is duplicated by 18
MC-142048
Permanent lighting glitch in woodland mansion; fully enclosed room gets sky light
Resolved
MC-142124
sky light does not dissapear
Resolved
MC-142314
Light level will not drop below 15 even with no light sources
Resolved
MC-142639
There appear weird skylight in some enclosure space in old saves
Resolved
MC-143364
Light level in dark room at level 13
Resolved
relates to 3
Attachments
Comments 31
Another situation is indoor is bright and outdoor is dark,(skylight exchanged between indoor and outdoor)
[media]
I believe this is why I can't turn off my villager breeder – the doors still see the sky no matter what.
Yup I have had this same problem with my mob spawner!! Even when it’s pitch black outside there is still plenty of light inside the spawner
Confirmed for 19w09a, MC-139446 has been fixed, abnormal skylight won't be created in 19w09a by running /fill command, but existed abnormal skylight didn't be removed(included created by running /fill command and created by rejoining the game)
@unknown, your issue is MC-149518.
Thanks for pointing that out. I just went to check that out, but I'm still quite confused with the difference between these two bugs...
This ticket: There's light appearing under blocks without any light sources nearby
MC-149518: There's no light appearing where there are light sources nearby
I think that you are talking about MC-142134, in which no light appearing around light sources.
In MC-149518, everything described there seems to be identical to this ticket.
And there are two issues shown in my screenshot: on the right-hand side, no light is appearing around light sources, which is reported in MC-142134; on the left-hand side, skylight is shining through the concrete roof, as shown in the F3 screen, which matchs the description of both this ticket and MC-149518, I think.
Fry
Confirmed for 19w08a