Another thought based on this photo ...




The pads are the same, but maybe the holders are different versions? Is that possible? You can sorta tell at the end of the holder (in yellow) that it looks like a different design. At least switch the two pads between the arms to see what effect that has. Check the rear brake to see if those holders also are slightly different. Obviously, the Dura pad itself didn't change in overall length, but maybe this particular KS holder did change. This could just be partly the issue and not the complete answer. The earlier pics weren't very clear about a perfectly centered wheel.

As far as I know, all of these Dura holders are specifically L or R, not both.