Uh, what's with the pushbackers for all AI traffic disappearing?
Are you SURE pushback tugs disappear for "ALL" AI? Because what you show in your video, is only ONE pushback tug invisible, which is the one on the parking position next to the one you were in.
That can happen if some parking spots are close, because GSX removes all default ground vehicles around your airplane, using a radius that is proportional to your parking radius (to be sure everything is removed from your parking spot), so if that overlaps a bit the nearby parking, it will remove ground vehicles of the other parking as well.
You might be able to adjust this by lowering the parking size of your parking in the customization page.