If a smaller cage doesn't work (and yes, sometimes that works) have you considered trying a tub? Some will push in cages with front opening doors but won't in a semi-opaque tub. Not ideal of course but either is hamburger face. Hopefully the move of Gerald will fix it.
I wish there was a magic formula to get them to knock it off. "Like, come on! you are doing this to yourself, stop it!" (that's me, admonishing a pusher lol)
