Can confirm that it happens on 1.14.1 Pre-1, haven't tested pre-2 yet.
I don't think this is this resolved. Seem to be server only since i cannot replicate in single player.
Steps to replicate:
1. Find an igloo with a basement
2. Cure the zombie villager in there
3. give him a profession
4. Trade with him and lock his trade for the day
5. Keep trading until he raises prices.
6. There are no changes on the GUI about the change, but if you give him say a stack paper, he will take more paper than displayed for the emerald.
I run a linux CentOS 7 server on a VPS, i restart my server with --eraseCache and --forceUpgrade, they fix the lighting glitch for a little bit until i go to the nether and come back.
Steps to reproduce:
Make a world
light up stuff around, caves, etc.
Go to the nether for a minute
Come back and some chunks are now entirely dark, this is easier seen in spectator mode.