Yes. It's a bug. They are working on it now. Has something to do with Evil Eye and Ally Attack champs.

As I understand it, "Because the boss drops an additional bomb when TM controlled, if the first hit on the boss is with the A1 of Evil Eye DURING the ally attack, then it freezes. Once all champs have hit the boss normally with A1 and triggered Evil Eye, it then doesn't freeze on next Ally Attack."