During the fight with Abeix I used my commander hero to use command on an Umberdroth I tamed. However, while it did give the next turn to Umberdroth according to the initiative tracker, the commander hero's turn started again. I ended it, it started again, and it did so every time it ended normally or via me using the "Pass" button. Thankfully, the cooldowns progressed, so I wasn't stuck in an unwinnable situation, killing Abeix with flame dart (or whatever that spell was called) spam.

I also didn't get the achievement for it. The area was "healed", though.