Why did the A.I. just auto win a ground battle?

[killymm]

I'm playing Thrawn's Revenge 3.1, but I forget which campaign I'm playing off the top of my head (I don't think that the actual campaign is relevant to this event).  I'm playing as the New Republic and one of my starting planets was Contruum.  My space forces were crushed by Zsinj and I prepared myself for a long bloody standoff on the ground.  I repelled his first ground invasion and was in the middle of his second when the game said that I had been defeated and kicked me off the planet.  None of Zsinj's ground forces had even made it to my base yet.  I had tons of ground forces and none of my structures had been damaged, but I still randomly lost.  Does anyone have any idea what may have caused this?  I certainly don't want it to happen again...

[k]

In ground battles there are landing sites marked with a special floating arrow that when controlled give you the victory. As a defender you have to protect that specific landing site at all costs, as an attacker when you control it you win, regardless of the other battle conditions.