Battle just randomly ends?

[recentiy03]

I'm not playing timed battles and I had broken through 2 sets of gates and was waiting for my ram to come and break down the final set of gates when all of a sudden the timer started...I thought that's odd but noticed the meter said I had killed 96% of them and I had more than 50% left so I saw about 10 spearmen standing in the center of their final gate in the citadel and assumed I won...but...no....I lost....what's the deal? I am not playing timed battles and the AI just stole a very hard win from me.