Are they moving to the exact center of the map? This seems to be an aspect of what I call the "0,0,0 point bug". see:
http://sto-forum.perfectworld.com/sh...d.php?t=479121
In space it relocates units to the center. Exterior ground relocates to a point outside the map. Interior ground is less predictable. Probably in part because interior maps have a variable 0,0,0 point. In part... the behaviour isn't uniform even taking that into consideration.