Thanks for bringing that up and I really appreciate the feedback! I'll be sure to look out for that error in the new version and appreciate the details! It's been several months since I messed with the old version so I honestly can't say specifically (I completely remodeled my trait system for the new version so it works differently), but I believe there is a chance of gaining either cum or piss on cleanup as well as the primary way of force-feeding the desired potion (cum or piss) to the person until they gain the trait. The second method is far more reliable, as I recall. Hope that helps for now!
Made some more progress on it today and hopefully with have a playable version in the next week or two. I will likely release it as a separate mod (leaving the old one up for now) as it is completely rewritten from the ground up. That way the old option will still be available for those who prefer it.