It's only this build that I've been able to have HDR on. (Looks great at LR with Skip BTW). But I turned it off to check the FPS difference, and ever since turning it back on, I'm getting random appearances of psychedelic colours on the Skip windscreen and flag guy's face and periodic temporary (a second or so) blackouts of the whole screen. I had the blackouts in previous builds. You can see the weird colours in the race menu screen in the small window top right. I think uninstalling the race school mod, restarting the PC and reinstalling will generally fix it for a while - as it does my previously reported temporary graphics freezes that randomise all colours and textures when the screen freezes with the sound stuck in a loop. Again, this stuff only happens with rF2; not once in years of iRacing, any other sim, nor any other game. Also shadows on the road are arriving very late. And I'm still seeing a banding effect of different tones of blue in the sky.