My install somehow got hopelessly screwed up (despite my assiduous use of JSGME to install every single shader patch and Sol version). I was getting bizarre things like trees changing color sequentially at the Nordschleife, the the ground doing the same, then the sky was black. No permutation of Sol + CSP version + config files could get everything working properly at the same time. Adding to the misery was the fact that each time I launched the game, I would get slightly different artifacts - with no changes being made anywhere.
So, I had to reinstall. For the second time in 2 weeks. For the moment, I'm back to running vanilla AC + the best mods (URD, RSS, VRC, DRM, everything by Bazza) and...it's actually quite nice. Everything works. No weirdness. No crashes. No config files in 3 different locations (each one fighting with the other, plus being potentially incompatible with the track version you're using). The sun looks great - 100% of the time.
I know Ilya is a genius, but he seems to be going down various rabbit holes to satisfy his own curiosity, but meanwhile the project as a whole is getting really messy and difficult-to-keep-it-all-straight. New features are relentlessly added, meanwhile really basic things like AI cars turning on their headlights properly or tracks running all their lights during the day (both of which can kill FPS) remain unaddressed. There are so many gameplay bugs, I gave up trying to understand them all.
I'm starting to wonder if a lot of people are just adding mods, running a couple of laps and then assuming it all works. It doesn't. Not compared to vanilla AC. I guess if you're bored with AC as a driving sim and are just into performing daily updates and/or tweaking your install, the current situation is tenable. But if you actually want to run a race, you're much better off with vanilla AC atm.
I really wish the CSP project would pause, stop adding new things (of questionable value to a driving sim), and work on getting the current features working consistently.