Ideas
I’ve just run into this bug. It’s my first time playing a house with multiple teens for a while.
I’m playing the Price family in Copperdale and only Savannah gets to have the full high school experience. If Sydney and Kevin get to go as well, the game doesn’t recognise that they’re at school, even though I can control them there. When school ends and after-school activities start, Savannah goes off with no problem, but Sydney and Kevin stay at the school, I can’t send them to their activities, and so they get the red flashing sign that they’re late. If I switch to their home lot I am able to bring them home and send them to the activities from there.
More recently, the game didn’t even send Sydney and Kevin to school at all. I didn’t even get the pop-up asking who to follow. Savannah just went off on her own, like younger kids do, while Sydney and Kevin were left at home with no option for me to send them to school! I had to get them to take a vacation day or phone in sick.
I’m currently playing without mods or cc, although I have used MCCC in this save in the past. And I’ve been using the original high school that came with the pack.