So, I finished the first series of four races, wandered around the menus, noticed I had a free car left, the FnF Dodge Demon, selected it, picked a design, hit the Buy for Free button, and the Xbox has been sitting at the spinning progress bar saying Saving… Saving Content. Please Don’t Exit Game for over ten minutes now… at a bit of a loss how to proceed.
Update: Crossed my fingers and exited game, no negative effects apparent so far.