Yeah the focus is kinda weird sometimes, you can mostly see it on bosses.
I first though Stormfiend focused any target dealing a decent amount of damage to his back, but it seems sometimes he keep on focusing and pinning down our host while I destroy his back, and sometimes other boss just keep on focusing the elf (usually me, but happened with other elf on my team) while me AND the host are bursting him down and the elf is dodging around and blocking.
It feels weird BUT I like it in some way. It makes ennemis unpredictable, and you can never know what they’re actually gonna do x’D