Warden's keep dlc bug

Hi all,

I'm writing here because I have a bug with the Warden's keep DLC.

When Avernus need to close the veil, It just stuck near one of the summon circle...NEAR, not ON it. So, the fight against the demons doesn't start and i can't complete the quest.

I don't have a sorcer with the Fireball (Yet) for push him on the circle and I don't wanna use console for just jump at the end of DLC, It's ridiculus. Someone can help me?