If the feminization process was performed under tight control using a true female plant that has been proven through time and again not to herm under stress, then there should be very little chance of getting a hermie. I say that because in genetics and nature, nothing is absolute. And also was the true female really a "true" female?
I don't know about the seeds being true females. I've heard (true) feminized seeds are little 'clone packages' of the mother seed plant. A clone is the same exact as her donor. That would mean all true females with no herms.
Hick or someone with greater understanding may be able to shed light on this interesting topic. I have hit a wall.
I think PB covered it pretty well.. "control, conditions, and method".."in genetics and nature, nothing is absolute."..
that being said, .. theoretically, a "true female, chemically reversed, and used to pollinate another true fem'," by genetic law, should not contain the male chromosome... ie.. a zero chance of male(staminate) flowers...