[Error Analysis] Sim can't return home

So an update after sending 3 sims to university:

I have one duplicate sim, but it doesn't seem to affect game play. The only other thing I'm doing differently than I did the second times, is not saving while at the university. That is, one new save when the sim gets there, updated save after sim gets report card, and updated save once sim arrives home safely.

Latest trip: Sent 2 sims, all seemed to be going well and then one of my sims got stuck swimming. She swam out of the swimming pool, down the stairs and onto the sidewalk...all very amusing but frustrating. Reset her, which took away her progress bar and she wasn't able to go to her classes, though she was still "enrolled;" had her drop out and return home while the other stayed and completed her degree. I'm not inviting sims to graduation and I'm getting to the ceremony early. Made it back straight away this time without any weird glitches at home either.