These mobs do an unreasonable amount of damage via their Unleashed Souls attack/spell. My Warlock has about 4.5k ward at idle and in a regular level 80 uncorrupted mono, with maxed resists and 20% armour they drop me instantly. Hardcore death out of nowhere.
I went back several times to double check their damage, it’s completely out of line for a regular mob where up until now my ward has never dipped below 2k. Even with a reasonable amount of mitigation there is no way to predict that kind of damage from these mobs.