The Phaarly Megalith (unique map) invulnerable and stuck, preventing map reset or town portal return

I was completeing The Phaarly Megalith unique map. As I got to a point where two bosses spawned, Gozen Rebellious Rustlord spawned inside the corpse of a past Boss. This has created a situation where the boss can't be interacted with and vice versa.

I can get the boss to attack via a dodge roll near him, but other than that the boss does not interact or do damage to me and vice versa. This invulnerable state has kept me from returning to town, resetting the fight, or finishing the encounter.

4 weeks later i 'm in the same situation :(

Also experienced this today, with a later boss spawning inside the corpse of Goran.