Lightning Warp/Betrayal/vorici/fortress immortal

Not sure what is causing this, I think it might be lightning warp.

When the fortress spawns in a map, the one with the 3 doors, sometimes I warp inside the fortress before the door dies. The door goes immortal and so is the boss inside.

In the last two cases the boss was vorici. I get him to 0 energy/0hp and he wont die.

I'm unable to leave the fortress. teleporting out and back in does not change the problem.

I'm using cyclone+cast while channeling+lightning warp. Also using lightning conduit of the heavens in mjolner.