I was finishing searching through auction winnings, when I spotted this on a quarter. I think it is likely just extreme wear, but the shaping was too linear to just take as that! I took some liberties of marking a second photo using MS paint with the area's I am spotting.
I an see the wanting to find errors/variety's but anything that is in that condition the second punch should stand out.
It looks like the S took a small hit on the right side and the wear has worn it away. Not an RPM but a good eye.