Hey!
I know it’s been weeks since you posted this, but I just ran into the same issue. Figured I’d reply with my fix, in case anyone else has been scouring the internet for an answer like we were.
First, I had Aza and Marisol in my party. Don’t know how much that affects it, but Marisol did warp inside the room. Don’t know if anyone else would do the same thing.
Throw a Distraction Device as close to the door as you can. This made the Cultist hostile and get so close to the door that my companions could attack him. My attacks didn’t do anything, but they killed him eventually.
This at least lets you progress Aza’s quest, though you still won’t be able to get into the room.
