Hmm. The jungle's stalk grows just fine for me in testing. Both it and the cave progression blocker require you to pick up at least one ingredient before leaving, but given your situation I would imagine you may not be doing that, hence running into issues? o: Do make sure you're on v1.7.0.1 please! (I should probably add a version number on the startup screen-- in order to do this you either have to hover over the executable and check its "file version," or if you're using the Itch client just click the settings gear next to "Launch" and then the "Manage" button on snack-wanderer-windows.zip!)
For what it's worth, each part can only be fattened so many times, and the butt ingredients from either the Jungle or Mountain alone are enough to max out the butt after Bottom Cave becomes unavailable. So I guess just pick a secondary part to fatten and grab some of those. You could also intentionally only pick up one boob/belly ingredient & then leave if you'd rather not see another part grow c: