Solved it!
I had messed up something in my settings.xml file, and the solution was to simply delete it, run the game, and the weird reflections were fixed.
Settings.xml can be found in documents/Rockstar Games/GTAV

I'm having a weird issue where my skybox goes brown/black in all reflections (most noticable on wet ground). I have tried different ENBs, tweaking settings, removing reshade, turning off all MSAA, SMAA, and FXAA, and the bug is still there. If anyone knows the cause, or have any fix, it'd be much appriciated
My guess is that some file has been corrupted, or placed wrong, as the ENB or Reshade doesnt seem to be the cause.

Here's an example:

So every time I try to install a mod with the .OIV format, I get this message. I have tried restarting OpenIV, restarting my pc but nothing works.