You best ask the manufacturer who made it what they used as a final coat (if its got one) as i'd use a similar product to re-coat it after its been rubbed down. I'm guessing its either gelcoat, paint laquer or varnish.

All composite parts exposed to sunlight should be protected from UV rays, it sounds like yours has no protection or if its not been long on the car then it'll probably be heat related instead.

Is the vent near the turbo? The hot air exiting through the duct may be hot enough to effect the surface coat, the normal resin systems are only rated to 80 degreesC.