EDIT:Totally nailed down the problem... Not the "Stock Car" ai setting. narrowed it down to a car mod... The Santa Car! I believe the Stock Car Ai setting called up that car.
On a side note my game kept crashing when I tried to race on Sandpit 1 track... I disabled the santa car, and now I am able to race on Sandpit 1 again. I let STR Mods know about the issue over at the Steam Workshop.