I get the same issue when my character briefly goes herm: my main Champion is full catfolk with only minor TFs (raising masculinity, thicc ass, reversing an accident oops) and as soon as I grow a dick I immediately become a human despite nothing else's changing.
It might be connected: I don't know coding, but I'm inclined to believe it's an issue with certain tags. Catfolk have "human" tags for most body parts, really only deviating when it comes to tail and ears. My thought is basically that once something else gets added that is explicitly not a catfolk racial trait, such as dick-n-puss or draconic wings, it tips the balance towards "human with some TFs" rather than "catfolk with some TFs." I think it might be pretty difficult to fix, though, since it involves a core mechanic that influences a lot of other things.
Don't quote me on this, though, since it's really just an uneducated guess!