I swear I went through an entire playthrough without seeing this "feature" until I started a mage....
. Like y'all I can't figure out if its a gltich or a feature. If its a feature its a pretty crappy feature. Like. I get having a feature that adds travel dust to your clothes, but on my mage the entire lower half of my body just turns tan while my upper body stays spotless. There is a button that turns of persistent gore, why not remove the dust as well?
It seems that more flexible pieces of armor (the coats that have the tail, or the giant overcoat don't seem to suffer from this. Metal bits of armor also don't suffer, but pants, lower robes and boots all turn into the pajamas you wear around skyhold.