C/F turned grey

A friend of mine has the same bike as I do with carbon fiber bodywork. His bodywork has turned grey with age. What do you guys think caused the bodywork to turn from black to grey with time?

The resin is crap, and/or it wasn’t well protected. This is why parts should be painted!

or it wasn’t CF, just coated glass, and now the coating is fading.
CF is carbon. Those colors don’t run!

… or there is no any UV Protection:confused: .