Right. Driver door only. No scuffing on the plastic or metal sill.
It appears over time the door action rubs on the weatherstrip and will wear it out.

Just thought others might have this issue and before rust begins on the sill you can treat the area.

 

Got a new 2013 Suburban last summer. This winter with only several thousand miles I had to take to dealer as I had rust already due to bad rubber seal. As you say the water runs into seam and water collects and rusts out door sill. Seems poorly designed. Other than that love the truck.

 

Check your weather striping (there are several) to ensure they are all attached correctly.