Iron Maiden pro has a small bug where a ball can get stuck behind the upper left pop bumper if a ball lands on the plastic behind it. This is because the plastic is lower than the pop bumper in front of it. The fix is super easy. Simply remove the nylock nut holding the lower portion of the plastic onto it's post. Then bend the plastic upward and screw the nut onto the post until just enough of the threaded post is exposed to be flush with the top of the plastic when it is put back down in place. Doing this raises the plastic to the point where it is the same height as the top of the pop bumper and any ball landing on it will now roll right over and off of the pop bumper. If you want to make sure the plastic stays securely in place you have two options. One would be to get a wood screw the same as the upper one that holds the top of the plastic in place, drill a hole into the plastic a couple inches below the top screw , and screw it into the wooden side rail. If you don't want to drill another hole into the plastic you could just bend the plastic back up and put a good drop of clear silicone on top of the lock nut and use that to glue the lower portion of the plastic back onto the post. Silicone is easy enough to pull off if you ever need to remove the plastic. Either way will securely hold the plastic in place.
Picture one: stuck ball
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Picture two: moving locknut from above plastic to under it to raise height of plastic
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Picture three: plastic at its new height flush with top of pop bumper
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