Zalmarath, The Colossus Bugged - Blocking Progression

Not sure when this happened but I am in the campaign and Zalmarath keeps becoming untargetable or 1 shots me. Have attempted him multiple times and im currently stuck in an endless battle that I cannot attack him and he cant hit me.

Please fix this asap because I am unable to progress in the game on my witch.

Just did a hard reset of the instance, unable to progress still. Please fix the game so I can play. Goodnight

I am also having this bug and another where Zalmarath becomes totally impervious to damage at random parts of the battle, making it almost impossible to beat.

https://youtu.be/LwGTXooPlgE
This clip is of him not taking damage.

I've also dealt with the camera glitch bug on top of the minions one-shotting me. Not sure I can keep this up...