Soloing Return to Karazhan on regular Mythic as a 120 mage. During last boss fight you need to follow the boss to different ships. As I touch down on the second ship the encounter resets and I get booped back to where the encounter begins and Viz’adumm spawns within a minute back to starting health. I have tried multiple times… started killing him slowly in case that was the issue and still happened.
It seems like it should have been fixed by now, but apparently not.
My solution was burn the baddie down before the third ship, but in my case he was resetting on the third ship, not the second. YMMV.
It is odd that he is even reseting at all, since he should be casting a portal spell, which gives you time to get to the ship and then to him.
Gotta love blizzards spaghetti code.