This has happened a couple times but recently I noticed it happening after I went to a lot with my sim, switched control to a sim who was back home, then brought her home and she returned with her current milestone's requirements reset. She is currently at the Successful Lineage milestone of the aspiration of the same name. She had completed the first two requirements for the milestone. Not only have they been reset, she cannot have her mentoring count towards the aspiration requirements. I've gotten her to mentor her son in painting and charisma and her mentor count still says 0. I've debugged her and right now I'm repairing my game just in case, so I will update this when I see her aspiration being updated appropriately.
No mods ever, CC a while ago but not now, on a mac, fully updated game.
Edit By Crinrict: Adjusted Title fit migrated bug report: [ARCHIVED] Aspiration Counters (visually) reset | EA Forums - 11425202
Archived thread had around 55 me toos