This has suddenly happened in my game. I've only experienced it on the one lot so far, but before my Sim moved in, it had met all the requirements. Now that she's there, attending university, it says the lot isn't complete.
The odd twist is that she's still attending university as normal and she has roommates. There was a weird moment where one of her dormmates threatened to move out and then did the next day, since her living conditions weren't met to her standards.
I wasn't sure if it was a mod issue, since I haven't tested it without them yet.