Quoted from Mudflaps:
Well that was fun.
Ball kept getting stuck behind the demogorgon. No amount of nudging would let it out. After getting two caught back there, I had to tear the game apart to find that one of the gates popped off. [quoted image]
This is a known issue with the early machines. Have not heard issues with this in a while though. It can be adjusted to not pop out by stretching it out. Just make sure it doesn't bind when you put it back.