Pathfinding works incorrectly when actor is moved from one interior cell to another
Just command an actor in one Guild of Mages and tereport with him to another guild of mages.
Since actor's AiWander still uses an old pathfinder, the actor can try to move outside of new cells bounds when the command spell expires.
In vanilla engine actor just stays in place in this case until a full game restart. It makes me thank that pathfinder in Morrowind is a global non-persistent object, which is cleared when player quits the game.