I don't think you need that workaround (honestly not sure what other effects it might have)
the only place it gets added is in expansionsetup.gd (last function):
func setRaceBonus(person, increasestats) (don't look unless you want spoilers on the hybrid recipes)
the function is only called in a few very specific places though. Should just be when an npc is conceived, generated (plus special cases for player and starting slave), or created through Slime breeding. The code for the races is in there. Pure Nereid gets: bonus_courage -= 10 so negative courage starting out is possible. If she had -10 and you added 1 point that would give you -9 courage. Also, there is a known bug in Aric's that causes jumps in the displayed vs actual mental stats that are fixed once you start adding to my understanding (and I've seen it lots of times in gameplay). I think that's what you're seeing in that Demon/Orc hybrid.