I am pretty fed up at this point. For the second time this week, hours upon hours of progress have been completely blown away by some sort of cloud syncing issue.
Steps:
I play the game for hours (which I am no longer going to do until this is fixed)
I enter a vehicle, multiple times during play, ensuring that the "saving game" prompt is on screen each time
I decide to go to bed at 2 am after playing waaay to long, and making lots of progress
I enter a vehicle before I quit, and again ensure the "saving game" prompt is on screen
I load the game the next day and am greeted with an older save and all my progress is gone!
This is the only Xbox I am using.