Front drivers side brake noise

Got a brake problem. It’s some kind of grinding or scraping but only drivers side front and only some of the time after releasing the brakes after stopping. I pulled the wheel and inspected and pads are good, rotor is good and caliper pins slide freely and no corrosion that I can see. Caliper looks in good condition. Only thing I can think of is brake line can sometimes degrade and/or swell which doesn’t allow brake fluid to go back and forth easily. Any other ideas? Supposed to warm up here in Colorado by Friday and I will tackle it again.

Scot

 

I can check again but backing plate seemed fine. It had good clearance far as I can tell.