When I went to high school with my first two teens and joined after school activities, they automatically had a rival that could become an enemy rival if you foster the animosity of that relationship. However, when their younger siblings joined high school and an after school activity, they did not automatically get a rival – meaning I cannot complete the Drama Llama teen aspiration without cheats!
This seems to only apply when a new teen goes to high school and there was already a current teen. Basically, if my original teen sims had graduated before the younger ones aged up to teen and went to high school, it would've reset and worked properly, but because they were still teens, it did not. This also seems to apply to things like the first day activities (i.e. meet the teacher, meet the principal, claim a locker).
On a mac. Never mods/cc. Insanely frustrated that this game doesn't work properly ever.
Edit By crinrict: Added Tag to Title, Adjusted Title
