Huge perfomance issues on night races

Suffering from the issue aswell.

It happens on all night races and performance also drastically changes even if you start during the afternoon and go into night time during the race.

Was driving around in Bahrain, started at around 150-160 FPS, once the night kicked in, FPS dropped to 80-90 and some moments of freezing dropping around to 20 FPS also started to happen.

Tried around with different graphic settings, asked friends with better hardware than I have and the issue seems to be the same.

Not sure exactly what's causing this, if it's the fog or something else since it happens on all night races, even in Vegas where there was (at least to me), no visible fog.

Also worth mentioning that during the transition from the day to night, certain parts of the track start becoming bright and a lot of smearing around trees and cars start to appear in certain instances.