Yes, I have noticed that as well. I like it that it turns from the shocking white...screaming...I AM A NEW BAG...to a peachy...saying I am worn and used...to a great brown color that says I am LOVED!
Actually I love the peachy colour the most - I think that's the prettiest stage! The brown patina has a great vintage feel but for some styles it doesn't complement the overall design as well as the peachy colour. But it's fun watching the bag 'age'.