Ideas
I have an issue relating to pregnancy too - I had a sim who was pregnant before the update, like first trimester I think. When I came back to my file the baby was born, though I don't have neighboring stories on, and aging is disabled on households I don't play in. Both of the parents had no memory of the sim being born.
I play on Mac, have zero script mods (or UI mods? anyway the mods that change gameplay) and just a bit of hair and clothes cc, so it cannot be anything else than the update.
I tried to delete the baby because I wanted to play through the pregnancy and the birth, but impossible to do that through CAS or manageworld or anything. Impossible to do anything (than keep it, but I didn't want to, so for now I'm waiting for the bug to be saved before playing with that family again).