Gotta say this is one of the strangest I've encountered. I know it's already been reported by multiple people that prom has simply disappeared from the game since the most recent update, and I am one of those people. However, in my latest save, not only did my Sim (which I started as a Teen) not get any options to go to prom, but she is also getting the event for high school graduation every week. She is now three weeks into being a young adult, about to graduate from university, and every weekend she still gets the invitation to attend high school graduation.
Some additional details:
This is the first Sim I've ever had that has achieved valedictorian. Not sure if that is a factor in this bug or not. She is valedictorian every week. I will update after she graduates from college to report whether or not the high school graduation is still happening.
I play on PC, and I do use mods/CC. I have tested the "no prom" bug without cc/mods and still had the same issue, but did not play far enough into that save to test this one. I will try to do so in the next week or so.
Her fellow graduates are a mix of the ones she went to HS with, with the occasional newly graduated Sim that has aged up to YA. But for the most part, they're her previous classmates.
Anyone else run into this one yet?