What you are describing is what happens when new (to this save) EPs are added. If you haven't only just added Uni (Seasons, ITF) since last having played these saves, might it be the case that the EPs failed to load at some point and are only now being seen as "new again"? Are these saves playable and other than locked wishes, have your sims lost any progress in their lives (skills, careers, relationshis, etc.)?
Also, not sure, but it sounds like you might be retreating to the Main Menu after having loaded one save and then trying to load another? This is never a good practice, the game has a gltich by which the contents of RAM are not always cleared in between world loads. It's a pain, but it's always best to quit entirely to the Desktop (or Origin) in between loading up different saves or starting a new one.