Color fading/wear cycling pants at seat bones/saddle contact points

I invested in some proper cycling pants this year, Castelli Aero 4.0 bibshorts and Castelli Meno wind bibtights. This is only some months ago, but already the pants show signs of wear right under my seat bones. The color is not full black anymore but is turned white. Is this normal or is there something wrong with my saddle? I do also ride my bike in bad weather conditions, but always wash of the dirt when I come back.