I played a predator (PC, steam) in quickplay.
One of the fireteam members in my match was a T-posing headless corpse. It moved (never breaking t-pose) apparently under player control but could not be hurt or apparently couldnt interact with anything (since he didn’t try to finish mission in this state once I had killed everyone else.)
All fireteam members were playstation players so this bugged one must have been also.