Xenonauts 2 - 1.23:
Units at the base of ladders frequently (usually) can't seem to find paths to the top of the ladder. This happens on every mission.
It was my assumption that this was simply an issue of getting line of sight to the top of the ladder, but it clearly is not. In the shot below, the pathing issue occurs even when the soldier at the top of the ladder turns around to give unobstructed sight on the arrival point.
Potentially related, soldiers frequently refuse to consider the possibility of vaulting a low wall or window. This causes them to only consider an extremely long path winding all the way around, or in some cases, refuse to path entirely.
My earlier theory was that this might be caused by units in motion blocking paths, but having tested this is not the case (it can happen on the first action of a turn, when nothing should have moved).