Genetics from either parent will carry over to offspring.
It's been done (though not sure if it's been done with yellowbellies in BP hybrids), in fact one of the more popular morph hybrids out there are 'jagpondros' (jaguar carpet python x GTP). They very obviously display the jaguar trait inherited from the carpet python parent.
The YB trait is subtle enough that if you hit the odds, with the usually low success rate of getting eggs, and it gets passed on, the rest of the crazy stuff going on might mask the YB influence.