In one specific chunk that has a structure built high above it, placing a light source and then removing it causes the entire chunk to drop to zero light all throughout. The video will demonstrate better than I can explain.
I am using the latest release of Optifine.
Thank you for your report!
However, this issue has been closed as Invalid.
Your game, launcher or server is modified.
If you can reproduce the issue in a vanilla environment, please recreate the issue.
Any non-standard client/server/launcher build needs to be taken up with the appropriate team, not Mojang.
Any plugin issues need to be addressed to the creator of the plugin or resource pack.
If you have problems on large servers, such as The Hive and Hypixel, please contact them first as they run modified server software.
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