This sounds like this is likely a bug with the pathfinding. There’s an “NPC Zone Guides” button in the zones tab that might help:
But dangerous terrain is already marked “try to avoid” internally by default. I’ve noticed that sometimes the NPCs can still end up walking through zones marked as “avoid” while trying to get to places past those zones. I’ll make a note in the bug log to look at this and try to improve the pathfinding.
Thanks for the report 👍