Builtin fog works great but when using Linear space and you lerp fog colors, then you get weird color changes, like fog being red, then green, etc…This just happens to terrain trees i think, or at least is the most noticeable. I tried to fix it but didnt find a way, so i tried using a fog pass in the tree shader but doesnt work.
Tried the example in Fog + Glow = Glowing Fog - Unity Engine - Unity Discussions