I hate all the dupes on here, and I did search, so hopefully this isn't one...

What I expected to happen was:
Blocks shown in achievement screen are lit normally (like in inventory).

What actually happened was:
Lighting of blocks in achievement screen responds to spurious external events.

Steps to Reproduce:
Easiest way:
1. Hopefully see blocks in achievement screen look normal, with normal constant lighting. If not, move away from everything until this is the case.
2. Place an enchantment table and turn so you can see it.
3. Open achievement screen and observe the lighting of the blocks changing.

Even better, have another player move around near the table to rotate and open/close the book and see the lighting changing as this happens. When you or another player picks up an item, the lighting briefly changes then too. Away from enchantment tables, it's affected by mobs. If you make an empty world where the only two entities are you and another player (or a mob), the direction the other player/mob looks affects the lighting. I'm guessing it's either the first or last "thing" rendered whose lighting gets carried over incorrectly to the blocks.