Checking the combat log afterwards revealed the following.

I get that epic spells should be exempt from some of the easy counters, such as Protection from Evil and Death Ward, which were both used during the fight, and not dispelled.
However, the combat log should not falsely state immunity, when there is no immunity.
As of writing this I realize that maybe it is a case of the immunity applying to the Confusion part of Entropic Husk, but not the spell itself.
If such is the case, then the combat log isn't exactly lying, but is instead misleading.