Trouble with achievements showing completed in My Games and Completed games
So for some reason my The Walking Dead Season 1 game I'm having trouble with my achievement number adding up to the amount of achievements actually completed on the My Games screen and completed games area. When I go into my achievements for season 1 every single one is completed and none are locked. It says I have 48/48. Yet when on the game details section of achievements for it, it says I have 48/48 with 500/600 gamerscore from it, and in the My Games page it then says I only have 40/48. So if I definitely know I've completed every chapter plus DLC and have done every achievement there could ever be without a shadow of a doubt how can I NOT be having 48/48 with 600/600 gamerscore and have a completed game?
Someone please tell me how to fix this, my pet peevish OCD cannot simply take this anymore.