When generating multiple structures on large scale the block lighting is not correct.
Somtimes it just has a border where it goes completely dark and those are not the chunk borders. This also happens in chunks that are loaded by a player.
I could encounter the problem in all Pre-releases and in 20w22a. Before I found there to be no problem at all. Singleplayer as well as Servers are affected
On rejoin the lighting is fine again
Linked issues
Attachments
Comments

Thank you for your report!
We're tracking this issue in MC-189415, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – ✍️ Feedback and Suggestions – 📖 Game Wiki
Please provide a screenshot with the debug screen enabled (hit the
F3
key) demonstrating the issue.