In some cases when generating a chunk, sand blocks generated over lakes being updated do not cause light updates, resulting in large dark spots. Though not mentioned in the ticket, this seems to be caused by the fix of
This issue seems to occur most frequently in spawn chunks. A very similar issue also occurs with snow layers over lakes (
MC-226437). It is solved by relogging into the world or simply updating the chunk lighting by placing a block, and is completely unrelated to chunk borders.
- Enter the following seed and coordinates (1.17.1):
- Alternative: enter the following seed and coordinates (21w37a+):
- Look down.
- → There will be a big dark spot.
Sand blocks updating upon world generation should also cause light updates, in order to not create dark spots.