I can confirm that this glitch is also present on the Xbox 360, and the causes seem just as irregular as they are here.
I doubt anything, from powers to whether or not we kill Martin, are the problem, I think this is just an error in the AI coding.

Any news on a fix, Bethesda?

did you collect all your unconscious bodies? That could be a reason.

edit: Bethesda doesn't make they game, they just produced it. Arkane is the developer

i also had trouble with this script in this mission, except it was the opposite of what others are having
the glasses never appeared on the table and the conversation between the overseer and the other guy never started
they just stood there when i looked through the keyhole, and no amount of explosions and fighting brought them out
i tried replaying the entire mission three times, always getting the same issue, until reading here that saving the guy tied up outside BEFORE going in solved it for some, so i tried that, and that fixed it

which is a bit silly since this was supposed to be my ghost playthrough where i only knock out the minimum amount of people and i have to knock out the guard to get this optional quest done that breaks the main quest

See http://www.gamesas.com/topic/1416667-strange-happenings-high-overseer-mission/ too. I wouldn't have started a new thread had I seen this one (I considered it a game bug rather than a PC-specific bug, but that may be wrong).

I know you may have tried this but this happened to me the first time so I re-loaded and this time shut the door behind me after I entered the meeting room and then hid behind the screen to the left of the doors that they enter through (the first time I had left the dorr I etered through open) and the second time they walked in and I was able to sleep dart both, carry Campbell to the Interrogation room and brand him and then carry the other guy to saftey.

I dont know if I was just lucky but it certainly worked for me