This happened to me too on my world started in 1.16. Never modified and survival only.
I am also experiencing this issue.
One thing I have noticed on this is that it can be temporarily fixed by optimizing world, but then it seems to happen again once a world is saved and reopened. This has now happened to me on multiple worlds and often happens in the same places.
This issue keeps happening on my world (created in Beta, updated through to 1.17, currently 1.18.1). It didn't seem to happen as much in previous versions. "Optimise world" does temporarily resolve the issue but before long the issue appears somewhere else or even in the same places.
Seems even worse in 1.18/1.18.1
Hi, world is too large to attach here, but here is the download link: https://www.mediafire.com/file/odrf86wtjmucoxo/Survive+221.mcworld/file