I am in the middle of shopping out my Congo and have the volcano ball popper assembly out. I looked at it tonight and put a ball in it and manually raised the plunger all the way up to see if the ball would get caught under the plunger. It doesn't even come close to fitting under the plunger with it fully compressed. You definitely have something wrong going on, possibly a wrong plunger length or something along the lines of that. I can take multiple pictures of mine if you need me to and send them to you. Let me know if there is anything else I can do to help.

John