Did you try to go fullscrean via button on the right corner? The problems with the walls should be solved with going fullscreen. its strange, that it lead to AI go nuts, I should take a look...
I think it must have been related to going fullscreen in the middle of the fight. Had I done it beforehand, it probably would have been fine. My best guess is that it has to do with how your boss fight moves around the screen after an attack pattern has started.