Rank consistently being reset when game closed

Why is it that every day I play Halo MCC my rank gets reset by one level the next day I sign on? I never leave/quit a game and I always sign off on a win? It’s been like this for 4 days in a row so far…

For example: I wouldn’t quit any games that particular day, would just get a 30 and then quit out if the halo game from the Xbox dashboard. Then the next day I turn it on and go search I’m one less level? I don’t understand?

I found an instance of this happening , that’s definitely odd. Passing off to someone who may be able to tell me whats going on with this. You aren’t crazy, Ill see if I can get an explanation or a fix.

Upon investigation, you quit a ranked game. This creates a penalty that is applied at a later game.