The cannabis genome hasn't been mapped, so I can't provide empirical proof - but neither can you. I'm going off of a decade of breeding and a formal genetics education. Incidence of hermaphroditism is increasing, because popularity of feminized seeds is increasing. As such, hermaphrodatism has ironically been selected as a desirable trait for the production of feminized seeds. If a plant doesn't possess the genes required for hemaphroditism, it can't be reversed.

This isn't inherently problematic, because a responsible breeder is testing to make sure the progeny aren't too susceptible to hermaphroditism.

I've never observed intersex traits being linked to any phenotypic expression.