I'm sure it's related to the single player lighting bug. But since I play on a realm affected I will add that we are having the same problem outside (so far) of the spawn chunks. See link for recent video after the 1.14.1 update. https://www.youtube.com/watch?v=2jNm5P-MMKU
If you go back further in his earlier videos, you can see when it first started. If it would help: we can add a Mojang tech to the realm or supply a world down load. I'm pretty sure David the owner has already emptied the cache and the problem remains.
In case it helps, we have a Realm where the problem remains. https://www.youtube.com/watch?v=2jNm5P-MMKU
The Realm I am on has this issue even after 1.14.1. It does not yet appear to affect spawn, just areas that get unloaded. Should this be reported separately as a Realm bug or are both being worked on?
An error occurred, please try again later, I've been trying for several days straight now.