The new event helmets will not go deep stealth. Video of bug[1] Has anyone else found any Infiltrator specific bugs beside this one related to the event?
If I saw the video correctly, the helmet only popped out of deep stealth when you "touched" him. That bug has been around a while (fixed and then broken again) with all helmets. I tested with the pumpkin helmet and had no problems (until another player touched me).