The section I'm on is about 39:00 in this playthrough: https://www.youtube.com/watch?v=vQbnGJgWbTY

The little bug scuttles into the hole at the top level no problem, but the other one refuses to enter the second hole. I can trick it to by icing it with the spear as it's running forward so it slides in, but then it just comes back out through the shut door, I guess because the internal state of the bug is not set to at rest in the game code.

This is obviously game breaking for me, but doesn't appear to be a common bug with, er, the bugs.