Zalmarath, the Colossus (Cruel Act 2) doesn't take damage on the right side of the arena

Bug Report ID: #3096953430

Hello,

I just defeated the Cruel act 2 Zalmarath and for some reason the boss wouldn't take any damage from any of my skills whenever he was on the right side of the arena. I'm not sure whether that's relevant or not (since I haven't had that issue last patch, or in regular act 2, I assume it might), but every time he was switching sides I was spamming Glacial Bolt and his freeze threshold was at around 80% at the beginning of the transition, reaching and getting capped either close to or at 99% during the move. It'd then decline over time as I was unable to deal any damage and keep it up.