Inan Hesh is frozen in slumped-over position

So today a guildmate and I were trying to get the Anger Managment AP.

We tried killing it after he Enraged and we both died at same time so the boss reset.
Then, we tried to attack it again, but the boss was bugged. None of our skill effected him, no damage - my Frost and Fireball passed straight though Inan Hesh's body as if nothing was there. The whole time he still attacked us using his red zones and purple areas, with his body frozen in a slumped-over position.

Attachment 124441

Same happens with mobs in a few maps, like bard's story.