Dungeon man : starting energy skill works only on 1st wave of coliseum
Spectral Dragon : immunity to physical damage is permanent
Bard: runed properly his white perma freezes the match while she slaughters the other team like hydra did back in the day
Plant soul: not neccessarily a bug but energy runes, 50% cons, and fury... just dumb. Add moon drakes legendary and its completely unkillable.
Feel free to add more, maybe the next update will see these fixes