Recently I was doing another playthrough of the campaign to collect all the Intel and skulls. When I was on the mission Battle of Sunaion, near the end right before your run around to see the arbiter kill the night, the arbiters character model was floating in midair. And it moved around if meleed. Eventually it floated through the ceiling and who knows where. Then as I came around the corner where he should kill the knight, the knight had the same animation as if the arbiter was there, but obviously he wasn’t. And he wasn’t there for the rest of the mission either. I also took pictures and video if this needs verification.