Apparent glitch in Justine DLC

[Kman]

i'm not very good with this kind of stuff, but for starters you're doing the puzzle wrong. you said he came into the second room right after you picked up the cog wheel which means you're probably not noticing the lever on the other side of the first door. if you pull that lever the door will close and it will hold him back long enough for you to get to the room with the machine with the cog in hand. i really don't know how to make it so he doesn't get stuck anymore, but maybe if you do that it will fix the problem.