[quote="DaveEllis">
No but I don't know if it effects the 360 version as well. I haven't seen any solution yet.
It's a serious issue, but tbh the career mode is so unplayable that it doesn't matter if you have a saved game or not. If they actually fixed the AI then you'd have to restart anyway.
[/quote]
It has been reported by 360 users aswell in the Codemasters forums.
Seems though only when you last exited the game after a saved R&D practice session does this happen. So apparently when you continue with quali and save afterwards this doesn't happen. Which could be true because Valencia was the first race I exited after practice, while being the 4th race of R&D tests.
So short-term solutions seems to be saving after quali or race rather than any practice.
Maybe you can do an R&D practice, save/autosave & exit, see if it corrupts your save? Seeing as you are not that into the game.