Yeah, my sim went on probation and then was suspended. Now she's stuck in that state and cannot re-enroll. I think it happened because I rotate and was not playing her at the time. The panel says she is suspended for 0 more days but the option to enroll again remains grayed out.
Just a warning to anyone who plays rotationally: your sim may be stuck on permanent suspension if you're playing a different family when they get suspended. My only option is to drop out, which wipes out all of her Uni progress.