During the mission, when waiting in the room where the High Overseer and Captain Curnow go in to talk, the conversation starts then suddenly gets interrupted right before they get to the door. Even if I am unseen, perfectly hidden, the conversation is interrupted and the High overseer and Captain immediately run to the hidden sanctum and the Captain instantly dies once he arrives there. I've tried numerous methods but is seems regardless of the path or means which I get to the Overseer's room, when I activate the event this bug will occur. I cannot therefore save Captain Curnow and I cannot complete the level undetected. The High Overseer can be killed or eliminated non-lethally to complete the level.
I can post a video later but this is a very glaring and serious bug and I'm wondering if other people have noticed this before or if the developers are aware of this issue.