The boss is stuck

I can't complete the Wetlands map because Gorian (the boss) is just stuck and doesn't move or do anything :D
I tried to leave him through the portal and just to the other end of the map, and come back, but he still sticks around in the swamp and does nothing
Has anyone encountered this?

https://ibb.co/xKDM9z0n

In the end, the map was counted as completed, but this killed bro remained in the ground and periodically spat poison at me (this was the only way he could take away HP)
Here is a phantom body of an already killed boss, or his restless soul, at least... which can even do harm, lol
I guess it's all because I play a witch :D