Gorian in Wetlands map spawned twice

Got Gorian down to a bit under 50% health while frozen, when a second one spawned.



Killing the first gave me map completion and dropped loot. Killing the second one *also* dropped loot.

Nothing about the mods on the map looks suspect.

Happened to me too, but the second head wasn't targettable and both became stuck and stopped acting.
Using checkpoints or portal didn't change the remaining second head behaviour.

here's a video of it happening:
https://youtu.be/6a1SYcYk6cM

I have encountered two bosses in this map every time that i've run it with a boss encounter. I believe this is intentional design, similar to the dual Tierney boss in the Woodlands map, which also both drop boss loot.