Okay, I'm mostly curious here. I probably have some non-borked backupo (I hope!) Basically, one of my adult Sim has decided to err become?? turn into... a child sim.

I launched up the game and went to play a family that has no children, just two adults in a relationship. Instantly, the school bus appeared on the lot...

My problem Sim has a child aspiration, his chemistry relationship panel is inaccessible (...although he is still engaged to his partner; please don't look, FBI!), and is a private school student (just like when he was a child), so he left with the bus, although he walked very strangely into it, obviously.

His body is not bugged though; I don't know if the family picture shows him in a non-appropriate pose because he lives in an apartment. I didn't check what sort of interaction options he has with other Sims because it was all just too creepy. I just quit without saving. I didn't check if there any other Sim with the same problem in the hood.

It's been a while since I last played this family. The only thing I recently did was to go and edit some lots in the vacation hoods (I was adding pool squares); my problem sim went on vacation to Takemizu when he was a child.

He is the same Sim which I previously had problems with a duplicate memory. I never kept that bugged save, I simply moved him into a different house that was not causing problems and he never got the duplicate memory.

I have not installed any new mods recently.

I tried to search for info online before I posted but did not find much help. I'm mostly thirsty for information of why this happens and how can I avoid it in the future. I try to make backups, but we all fail sometimes.

I'd like to know:
1) is it just okay if I ever get the same issue and just age up the Sim?
2) any idea what actually causes the bug?
3) do you think it could be that there are wider problems in the hood?

I'm sorry for the wall of text!! I'm sorry that I'm always coming here with some problem I'm extremely grateful for your help.

I would run Hood Checker and tell it to remove what it can. Then check him.

I had a recent backup that was all alright. I think there was something wrong with a lot in Takemizu because that's all I did between one backup and the other. Everything seems to be fine for now.

With hoodchecker I get a lot of relationship errors and such; every time I try to fix them, at least one sim always ends up with some problem like after fixing having a relationship with self and such :/

Those are harmless and HoodChecker can remove them. They just happen during gameplay without you doing anything wrong.