I should have noted the battle-type but I did not, sorry Bonk... I was busy though. The opponents were Feds but my AI "helpers" were Roms.
One thing I've noticed with the server kit in general is that somehow the AI factors into the mission results way too much...
Every time I've had "enemy" AI helpers survive, I've gotten zero defense shift. Even though I won the mission for my race, the fact that I received enemy assistance caused the DV to shift one for me and once for them...
So, with the Rommie AIs, the kit must have thought they were the primary force in the mission, and awarded the hex to the Rommies.