No clue what could be causing it, only suggestions for trying to fix it. I've never had aspiration issues with more than one Sim at a time, but I've them. Just yesterday I had a Sim whose aspiration simply disappeared. I took him to the Renuyu sensio orb to change aspirations, which fixed it. Have you tried that?
You said you tried resetting everything with batbox, did you try rerolling the LTW or cycling the LTW with it? Rerolling it *should* give you only options within the correct aspiration, while cycling it will be random. I have found that sometimes it only goes between two or three LTWs though, and not all of them. Not sure why. You can use testing cheats to spawn something similar in game if you want to try that- the Sim Modder. It's a little baby in a diaper standing in T pose. It will also give you the option to cycle LTWs, either by aspiration or all of them. I prefer to go with other options though, because that thing creeps me out. 🤣
For other options, there's waiting until junior year of university, when you have the option to change aspirations. You can also use the College Clock from More Awesome Than You. It has "My LTW is Lame" which rolls a new one for you. I won't play University without it because it also has other options that make playing Sims 2 University bearable.