Here's the official answer.
Quote:
The turret is unaffected by the repositioning from Stomp as it cannot be repositioned.
If this results in an awkward situation on the map, you just have to deal with it somehow.
I guess that means two characters in the same square? The AT-AT can legally enter the space but the Turret stubbornly refuses to move.
AT-AT -
"Grrr...." STOMP!
TURRET -
"I aye movin' fer yaow!"
AT-AT -
STOMP! STOMP!
TURRET -
"Clear off yer overgrown mechanical pup, or I'll give ya' cogaver!"
AT-AT -
STOMP! STOMP!
TURRET - [failed save]
"Awww nuts!!!"