I would suggest playing around with the switch the ball sits on, see if you can move the apex of the wire (more behind the ball) so it kind of gives the ball a helping hand through from stored energy in a compressed spring
.
Hope you know what I mean.
Might be enough to stop the ball getting jammed.
edit: watched it some more - see if you can play around with the mechanics a bit more to stop the ball geting kicked back while the plunger energizes.
