just got that, too. I forgot to disable auto-play. My therory was, that if the troll would not interact, he would do no harm. For my test now on autoplay, he activated his ability, which caused the bug.
So if you have a troll in your troopers list, put him in the easy levels (or bonus level) on ailing kingdom, pair him with 2 massive AOE damage dealers and play yourself, so that 3 basic attacks from eddie instant kill all 3 round without using the troll, thus getting the 25 points. I try tomorrow. Yet it does not fix, the problem, when you have the troll and want to use it, but you could use your trooper.