Brake discs - scoring

Anyone have an idea on what causes scoring on brake discs? I recently replaced pads and discs on rear wheels of my wife’s VW Beetle. Now after about 10,000 miles the discs are scored like something got caught between the disc and pads. Suppose it’s possible but have seen this before also and it puzzles me.

Generally it means something got caught between the pad and the rotor…or that you’ve tried to go beyond the normal wear of the pad until the hardware was showing.

Does your wife drive dirt roads?

No, my wife doesn’t drive on dirt roads. I did find that the dust shield behind the disc was pretty rotted through with rust. Probably some of that got in there also. Ialso discovered that both caliper pistons were seized up and I am now in the process of replacing them as well as the discs and pads, an expensive job even though I’m doing it myself. As of now, I’ve got about $300 in parts and shouldn’t need any more. I hope.