As far as I know, a trigger_transition is only to create an area which a transition can be triggered in, but won't happen the moment you step in. You can't make the grunt continue moving in the next map, he will be carried over, but only monsters are carried over, not paths/weapons/ammo etc. Also, the grunt is unable to follow the paths again in the previous map, because he only targets the path_corners when he is spawned. When carried over, he has no paths to follow (They aren't carried over), and when is carried back, he won't target the paths again. However, you could use scripted_sequences to make him move instead.