The bug

Several cases of chunks flickering in and out and not being rendered partially or entirely, persist in 21w41a and later snapshots. Sometimes, the game will not render some chunks that should be visible, like in MC-70850, which can last up to 20 seconds.

This occurs on all "Chunk Builder" settings.

To reproduce

1. Go to spectator mode and roll the mouse wheel up to increase flying speed.
2. Explore new chunks and watch.