@MKZ4345Alright everyone, I tested further in my affected save and found a new wrinkle! Hurray.
I went through a bunch of reddit threads and other answers hq threads to try and find a similar issue to see if it could give me clues on what might be the issue, and I found one talking about an error caused by a sim's unfinished book getting corrupted while a sim travels. This was sort of close enough to the problem we're having here in terms of the attribute error, so I went through my game's households and found that the house I was trying to move my sim into had an unmarked "song lyrics" book from when one of my sims was trying to write a song on guitar. Interestingly, these lyrics were written by a sim that had died, though I only know that because I remember, not because the book has any information attached to it anymore.
I removed the lyrics from the household inventory via selling them, and then tried to whole process again. This time, weirdly, when I would've been taken back to the select worlds screen and given the error message, I was only sent back to the select world screen with no error. I then loaded into the newly merged household with no issues.
But this is a wrinkle because, drum roll, this wasn't even the original household I was trying to merge this sim into! That original household had no objects in their inventory, neither household nor sim inventory. So I really don't fully understand what is going on with this glitch. The lyrics appear to have been the issue, but I'm pretty sure it's not supposed to send you back to the select world screen after merging into a new household.
Thoughts?
EDIT: I actually DID get a last exception for this! It did not, however, prompt the error message this time for some reason. I'm beginning to think it's either the sim I'm trying to move or the baby she has. Does anyone know if babies are still objects in the game code?
