I have the same exact problem, 2015 F1 50 4 x 4, I have a really nice Ford Tonaeu cover on it, on the way to our hunting spot there is a 2 mile stretch of just diced Stone Road, I have the drain tubes in the front corners of the bed, i’m wondering if the dust is slipping through there or through the gap in the tailgate, all of our stuff was loaded with dust.
