There is a chance the Enforcer used its repair ability and got captured while the ability was still active. The repair ability disables the Skarovas' sub light manouvering engines, which is probably why it couldn't move after it was captured.
Any ability on captured frigates that requires race - specific research will be removed so that the one who stole the frigate can not take advantage of it (so the owner of the Corsev cannot use the enemies' own techs against him). This movement bug also occurs when you capture an enemy Junsurak Sentinel or Kanrak Assaillant, when they had Charged Missiles enabled before they got captured. I am not sure if this could be fixed by the dev's but it is definitely still is an issue, be it a small one.