[Mod Edit - Profanity and user removed - D]
might have something to do with this
https://support.xbox.com/en-AU/xbox-live-status?xr=shellnav
I just had an achievement pop about 15 minutes after I completed it
Thanks. It just randomly popped up 2 hours after I completed the race. This game has been so glitchy I just figured this was another one.