Is new campaign first boss hear thing bugged?

[rook storm]

The fight involves beating down the minions until the heart is exposed to damage him.

So with my sorc solo,I took on the minions one at a time- frost bolting em one by one ,isolating each one from his buddies and then hammering them till they reached about half health,at which point
they all stood ,swaying around like they had swilled too much real good moonshine
They offered no attack or defense
The shield on the boss was still up
After a few minutes ... Nothing happened
Then, taking me somewhat by surprise... Nothing happened
They were all still swaying like drunken acolytes as I fell asleep.


All your Plat are belong to Sam