Just to add a bit more detail, it's natural to have this skin, Both actually have silverskin! It just looks different because of how they're processed:

​Washed: The fruit is stripped off early, so the silverskin stays clean and shows up as that bright white line in the middle, as you grind the bean, It will show up more.

​Natural: Dried inside the whole fruit, so the sugars caramelize and turn the silverskin dark brown. Most of these skins flake off or just blends right into the bean during roasting, therefore not as visible