Coloseum again bugged

Stuck at 90%.  All three Zeffo are being attacked evenly.  They all have less than 1/4 of a bar left of health.  One Zeffo guardian remains after whistling bird attack takes down the other two, when all three should die together.  Remaining Zeffo will not lose armor and no one does more than -1 damage.  Zeffo eventually just kills the remaining allies.