In Balanced Hackmons, it is currently impossible to have a Pokemon with a set gender to be genderless, despite reports from TI saying that in-game, it is. Whenever you try to set a Pokemon to genderless that has a forced gender, then it will simply revert back to the set gender. This is because unlike Male and Female, on the importable, Genderless does not have a specific icon to signify the specific gender, since all Pokemon that are Genderless cannot be anything other than Genderless.
My solution to the problem is to either add a genderless signifier along with the current male/female signifiers in the importable, or to simply remove the hardcode preventing specific-gendered Pokemon to be specific in Balanced Hackmons.