Green Paints

Most of the stock manufacturer green paints have issues. A lot of cars (V8 Vantage, Escort Cosworth, Fiat X1/9) that are supposed to have metallic green paints show up as a fuzzy matte paint instead.

Metal flake greens imported from previous Forza games are messed up too, what is a dark metallic green in FM5/FM6/FH2/FH3 are showing as bright solid green.

A lot of the reflections are toned down in this game. This results in the kind of issue you have encountered.