Can't hit Zalmarath, The Colossus with skills

Bug Report ID: #1970586317

He is taking damage from thorns and I can still be hit by his skills but my shield charge and resonating shield are not working as intended.

Having a similar issue. For me it seems to happen if I freeze him during his animation to go to the other part of the arena?

Had to deliberately die 3 times near beating him because of it.

It's not a reduction of damage, he literally is untargetable/unhittable.

If I only use Arc and don't ice wall it doesn't happen.