Put the summary of the bug you're having here

What I expected to happen was...:
Light to be consistent across all chunks.

What actually happened was...:
Some chunks are at a really low light level, right next to a chunk with a really bright light level, with no transition.

Steps to Reproduce:
1. Possibly loding a world from earlier snapshots, or the present snapshot.
2. Fly away from original spawning point.