I had stairs inside my house because it felt natural and pals got stuck every few minutes and sometimes could not get to the second floor at all. When I turned around the stairs (so they enter the second floor from the outside), everything started to work surprisingly well. Pathfinding is extremely buggy, but sometimes you can (try to) work around its limitations.

I do think it's just some of the pals. The little ones seem to have no problem going through doors or up stairs. But some of them just get stuck in everything. Like the fire Vulpix wannabe. Those things are constantly getting stuck on top of benches, along walls or in rocks. 🤷🏻‍♂️

And the bigger ones in general I don't think fit through doors. I certainly can't ride any of the mounts through 'em.