Watched some of my hotlap videos yesterday and stumbled upon this one, happened on the uphill part between Acque Minerali and Variante Alta.
are those replay-files a bit older? With the Hotfix last week, the elevation was changed at that part of the track. It seems that the car-model is still moving the old elevation but the Tires stay on track...
Here the Patchnotes from that Hotfix: 28-09-2017 Prepared files for upcoming events and content release. Game: Fixed a game crash that could sometimes occur simultaneously for several players at the end of multiplayer races. Art: Aquila - New driver animation Canhard R51 - New driver animation Cougar C14-1 - New driver animation Saleen S7R - New driver animation Color balancing work on the global light settings. More adjustments will be done to further improve in later patches. Imola - Additional tweaks and fixes, minor elevation adjustment when coming up to Variante Alta.
It's the other way round than... It is not solved with the hotfix - the hotfix with those elevation-changes creates that "bug". With the replay-files you will always see the latest version of car- and track-models. But the positions are saved from the moment you drove there. So as the elevation to variante alta was more flat than it is know, your car seems to drive in the underground...