There is a bug I noticed a few months ago that still haven't been fixed - a round glass plane in the back of the Tatuus formula cars in races. It randomly turns on and off, and is very distracting. No other cars have it, only Tatuus DLC. Of course, when I decide to record it for forum, it's not there. But you get the idea. I run mostly high settings, single screen on GTX1060.
Can't remember exact details but I believe it has something to do with the rendering of the exhaust effects. You can disable this in the player JSON file so you don't see it but it will also disable that effect for all other vehicles as well. I believe the setting to disable in the JSON is Heat FX Fade Speed. Hopefully someone else can confirm this.
I think this is what's you're looking for. https://forum.studio-397.com/index.php?threads/the-tatuus-pack-is-here.63469/page-9#post-1012619