I've noticed that since the last core update XBox stats are incorrectly saying that my total driven miles has only increased from 10,059 to 10,070 (it should be around 10,250) in two days, so anyone still chasing down the 10k achievement may want to check to make sure their progression bar is working as it's supposed to (a single Koln > Achen run should always display a tiny increase in white) because if it isn't then it'll be an ultra long haul to 10,000 miles.
Give it a few more runs and see if it corrects itself. The true stats are on the player profile in game, not the Xbox stats section.
It seems to be just the custom scenarios that aren't registering miles driven on either my ingame profile or XBox stats page, with the default routes + scenarios (using the 'explore' tab) working fine. I'll delete my custom routes and create some new ones tomorrow to see if it makes any difference. EDIT: I've just added up the miles driven from each individual location (11,216.53) and compared it with my current ingame profile (10,598.94) so it looks like this may have been going on for pretty much every custom mile I've ever driven.
