I have been having this issue with a few tracks now, I think its the csp. in game change weather away to a different weather and back and it kind of resets, in my case its odder, race starts out to dark, and gets progressively brighter and brighter,or vice versa, starts out to bright and then gets darker, but the sky stays the same, initially thought it might be cloud cover shadow setting, but, it happens on clear weather as well.
You can adjust any post processing filter exposure as well, open it in game and drag exposure to your liking. (sometimes need to change away to a different pp filter and change back.
note clip, same weather al the time, massively different exposure settings, so sometimes i just hit it a few times in sol weather till i find what i like,.