[GRO] Milestones: Peed on caregiver doesn't fulfill

I haven't updated my game to the latest patch, from last week (27th/28th February), by the way. 

I'm currently playing with twins, and have noticed that one of them only has two quirks. Usually the third would have appeared by now, halfway through infancy (I play on Long lifespan so infancy is 20 days and the infant has 10 days left until aging up). I triggered an example exception with Better Exceptions (since the Active Sim's traits are listed in the exception), and realised that my infant's third quirk is Free-Air Tinkler, so she often pees on her caregiver during diaper changes. Since this "peeing" isn't happening, the quirk hasn't appeared in game. Her sister has all her quirks. 

I haven't tried testing this in a game without mods and CC, but I will do so.

So I tested without mods and CC, the issue still seems to be happening. Hopefully I tested properly! 

Huh!

In my normal, modded game, the milestone just unlocked!! No idea why it suddenly unlocked now, when it hadn't previously. The pee appeared and everything. Maybe I'm just impatient? I'll have to go to my other save where I recently had infants (who are both toddlers now) and check if they got the milestone or not as I don't remember. 

Previously, my caregiver would react as though she'd been peed on and would get the associated tense moodlet, but there was no actual pee animation and the milestone didn't appear. As for the infant who had the "Free Air Tinkler" quirk that was hidden, I used testingcheats to remove that quirk and add in the "Loves Sounds" one instead. 

How weird...

So I checked my other save where I recently had infants. The older sibling did have the Peed on Caregiver milestone, but the younger one didn't. I think the older one aged up to Toddler before the January patch, though.

I cannot achieve this milestone, either. Been trying for about 20 days in-game. I also can't say whether it worked previously, as I've only started playing again recently, after over a year-long hiatus. So yeah ... can't provide helpful details.