Thank you! Ill look into this bug. Can you unlock the 17 star lock at the end even though it says you have 16? Or is the game not letting you unlock it? I've had others complete the game without this bug but I'll do my best to figure out what happened in your instance. Definetly dont want this to happen when you spent all that time on it. It's not easy to 100% it! Sorry that happened to you, what a bummer.
EDIT: I have a suspicion that the last coin you collected on one of the levels is missing an increment +1 event. it would have set whatever level it was to star achieved but not incremented the number. That would explain the map icon showing you got all the stars but still showing 16 over all. Plus would explain why others have got 17. The last coin they collected on whatever level it is would have had the increment event in it. I'll see if I can locate it and let you know what level it's in.