My Sims Never Go to Classroom Two, They're constantly going to Classroom One.

@mizamelia , my experience is the same as that of @Compulsivian .  Only the Exam prep is held in Classroom 2 and that is after school hours.  All classes are in Classroom 1, which make it seem less like an actual high school.  🙁
Also, I agree with @Compulsivian , in that I also think that this is by design.  Even the YouTubers who had early access to the game had all their students attend in Classroom 1.  🤷‍♀️