Molten Vault Boss bugging

In the molten vault, if the boss is stunned when starting it's phase in the lava, he stops and start to walk toward the end of the level without attacking.
While making the fight much easier, I don't think it was planned this way :)

Anyway thanks again for this masterpiece and keep rocking !

Bumping this. Happened for me too. Heavy stun in the lava makes him suicidal (walk and never target you).