I usually prefer to move my dormies in at uni, and play them to graduate. It can be annoying, but it seems to be the only way to guarantee the want slots. But the college adjustor is a quick enough fix.
I do that in smaller neighbourhoods, if I don't have many playable teens ready to go to uni. But in larger neighbourhoods with plenty of teens I just want to get done with the whole uni thing as soon as possible, and get back to the main hood. This is a merged PV/ST/VV, so I have plenty of teens to put through uni.
I find it strangely reassuring that this has randomly happened before in other people's games. At least I know my game is behaving within "normal" parameters and that it's not a Seasons-related glitch.