Breach won't close

Opened unstable breach, killed Vruun, breach won't close and I don't get my blood or wombgifts. Monsters just keep pouring out endlessly.
I had syndicate members spawn during the encounter, I killed one of them, bargained with them mid-encounter, so maybe the game thought the encounter was cleared for both mechanics or something, idk?

Managed to clear the breach. There was a mob marked as a red dot in the minimap that I killed and it closed the breach and I got my rewards. Not sure why I had to kill this mob specifically, since when the Marshal of Xesht himself spawns, you kill him and the breach immediately closes, never had to kill other monsters along with the boss, in hundreds of breaches I've never seen this happen.