One specific time this has happened was in Circuit of Americas. Restarting a free drive, the lights worked on the first race. Restarted the race and every car including mine had the lights off. Had to switch tracks and back to have the lights come on.
I’ve seen it in MP as well. Had it happen on multiple tracks, with different cars.
Just had a race in MP, having the same problem In most of my night races. So far I see the problem most in classic muscle races well for me at least