So for some reason a few of us are experiencing lighting bugs while trying to build grinders. On solid structures with no holes it still shows some areas spawn only when it is dark outside. Is there any known fix for this issue? Or something that can be looked into? It is pretty annoying.
Have you tried filling in the area and then removing it? Seems to be a light source withing your structure, possibly from a block not being updated correctly.
This has been haunting us. If you fill all of the open space with cobble or any other building material, break it, it will then go away. No idea why this happens though.
This usually happens when temporary lighting is unchunkloaded. (AFAIK) IE: Thaumcraft Hyperenergetic nitor does this and is the reason I hate it so much, it causes gross paths of light everywhere someone goes that are never removed until you build a block on the exact light source. I had the same problem when I played sky factory 3, as explained fill the area with blocks until the light source is replaced.
The lighting issue was part of the vanilla bug list that was never fully fixed even now in 1.10. Luckily in sf3 a builders wand some sand and ore excavation with a hammer yields some dust and a dark room.