It's becoming increasingly frustrating trying to enjoy this game when Playground Games and/or Turn 10 still aren't properly addressing some glaring issues with glitches, as well as problems with solo play and online competitive play.
In a single 24-hour period I have well over 750 miles driven in the Jaguar XJ220 (based on Forza Horizon 4's own per-car stat tracking), yet the game continues to show my tally as 0.12miles/20.00miles.
Nothing I do changes this from various types of continuous driving, to restarting both the game and my system.
So due to yet another glitch I'm unable to complete the Forzathon challenge. MANY of my driving team members have already given up on this game. I don't want to find myself doing the same, but the developers' handling of various issues often makes this seem an eventuality.
-edit-
Here is photo evidence of the car history, and the incomplete Forzathon challenge: