Like most folks, I'm not the original owner of my TZ machine. I noticed two odd flathead screwheads on the playfield, in the left spiral ramp. (see photo below) A few times, but not all that often, a ball will get stuck on the far one. It's probably become magnetized due to its proximity to the magnet there, but that's just a guess. Seems weird to have exposed screwheads in the path of the ball, but I don't have another copy of the machine to compare it with. Are these supposed to be here? They're holding the big solenoid that drives the ball diverter. Thanks in advance.