It looks like a healthy leaf, I don't see anything unusual.

Zeedman, it looks as if the leaf has been lightly spray painted gray. Updated picture

I don't see it either, but a grey dusting might be some kind of a powdery mildew? Did not know beans got that, but may be different in your area.

It can be treated it in squash by spraying with one cup milk to 3 cups water.

Oh, I think I get it! You're referring to the palest part of the leaf, most pronounced on the right side of the photo? At first I thought that was just light reflecting off the slightly shiny surface of the leaf, but if it's indeed white like that then I have seen that before on my own beans and it's just physical damage, usually mild sunscald or just the leaf naturally starting to die down and get a bit weird as temperatures drop.

Sea, Yes thank you!! It almost looks as if the leaf has been shaded in like a drawing! Thank you