Split And Move (to same Dorm) Not Working

Hi Sid, thanks for the quick reply.

Answering to your first edit, I did send away the kids of my sims to their teen siblings 😢 (They're gonna have a hard time handling high school, part time job and their little siblings RIP) and all the pets my Sims had, reached their expiry date 😢 There was no one except both the twin young adult Sims.

Answering to your second edit, both the Sims did get accepted into the same University or the option of moving in together shouldn't even exist. (I made sure my Sims were eligible for University by upping all their skills to 10 and receiving the acceptance letter)

Update : The Sims do move in together into a dorm but I have to restart the game for that because when I move in the 2nd Sim with the 1st Sim the game just kind of hangs/crashes (there is no way to know if crash or hang happens since there is no button to press to check)