So much for a bugfix, you actually replaced the old bug with an even worse bug. XD
When Vanaduke dashes into the bottom left corner, he gets stuck permanently and can't move or use any attack except the fire snakes, though he does rarely use his regular mace smash when he's not busy running in place for no reason. :P
Bug on phase 3:
http://i.imgur.com/JHPbz.png
I have a pic of it on phase 5 too, but the stupid falling debris is blocking the entire shot, so it's useless to show. :(
It's not a new bug, I've seen it a few times before the latest bugfix. Still needs to be looked into though.