Hello.
Several times I tried with a friend to pass the boss in Soulfire Dungeon at lvl 75.
First problem:
Under netcrotic shield - i get necrotik penetraion stacks. Under fire shield - i get fire penetraion stacks.
Screenshot with necrotik penetraion stack under the netrotic shield, when try to solo kill that boss; https://imgur.com/a/jgIEGFu
Second problem:
When ground switches to necrotic damage - boss immidiately damage with fire.
When ground switches to fire damage - boss immidiately damage with necrotic attacks.
Regardless of which shield is enabled, another elemental attack dealth deadly damage.
Not posible to walk out from attack.