To disable cross progression go to Options > Gameplay, scroll down to the Miscellaneous section and simply switch"Enable cross-platform Saves" to OFF. And Enable Analytics as well while you're at it, or not. It's your game to do with as you please.
Cross progression uses the new and glorious cloud technology to allow you to have the same saved game on all platforms! Soon you'll be able to store your hopes and dreams, as well as your firstborn there too! Happy times! Our benevolent overlords in their divine wisdom have decreed that. However, chaos and disaster can ensue if your internet connection is slow, as mine was today, because of maintenance work. My game actually crashed when pressed F5 two times quickly, and the game couldn't send my saved game to the dreaded cloud for storage and molestation. So disable it I did, and happiness returned.