Sometimes I would get this weird pathing issues with my companions. It seemed to start right when I got a sixth companion, or in my case Sagani. Basically when the party moves to their move location. One or more companions "stutter" rapidly in place trying to find a place to stand. It seems like the issue might be worse with a party formation that is compact, but it happens still in more spread out formations. You'll also get an annoying sound of rapid footsteps as the characters jitter.
I think sometimes even NPCs off screen can bug, because sometimes (once my own party starts bugging out) I'll hear rapid pacing from what sounds like an NPC off screen or in the fog that is.
This is a bug that exists in the current version of the game with both expansions.
The purpose of this thread isn't exactly to beg for bug fixes in PoE1, though that'd be nice. But it's to collect a number of issues that could be fixed going forward. Since Deadfire is actively being developed and that's where Obsidians focus and resources currently lie.