Act 2, Tor Gul the Defiler

Tor Gul's freeze counter stays at 99% the whole fight and is unable to be frozen.

I had the same issue at some points during the fight with the Titan Grotto boss, though only during certain attacks. It might be a counter-measure to prevent large boss AI/behavior from breaking. But it's still annoying.

Edit: I had no such issue with Tor Gul.