On Xbox One first gen. Fully updated game and console.
Problem easy to recreate, hard reset and restart have no effect.
What race: Breakout championship, Rally herous, 3th race Hockenheim ring, long race distance.
Car 1986 Audi #2 Audi sport quattro S1
Frameratedrop and stuttering from the start till the end of the race.
Just tryd the same race on my PC version of the game, same problem!