I don't know if it's a mod incompatibility, but it could not be.
Here is the issue:
video (streamable)
If the issue isn't clear right away I will go binary testing tomorrow (removing half mods over and over).

Chunks not loading just started affecting players using my pack as well. Removing bobby fixed it.

Chunks not being visible when there's missing chunks between you and them is expected behavior, that's the game optimizing which chunks it needs to bother drawing. Usually not a problem in vanilla because the loaded chunks are always a rectangle; bit unfortunate for bobby but not much that can be done without rewriting half the chunk renderer.

The chunks which don't load when you get close to them are suspicious though. Would need a way to reproduce to debug it though, ideally with as few mods as strictly required.

This was so long ago I don't really play with bobby anymore.