Slaver vehicles spawned on mountain

[Destragon]

This save was started on 1.03 beta 5, so I'm not sure if this has been fixed already when it was fixed that militia units with vehicles can't spawn on mountains.

So, I was wondering why these slavers aren't using their huge stack of tanks and vehicles to attack me. It turned out they spawned on a high mountains tile and are thus completely unable to move. The whole slaver vehicle army stuck in a mountain monastery.