I don't see anything wrong on the first image but I could be overlooking? Whereas for the others, it's possible the designs are intended for R6 use, not R15 if the glitch happens to disappear.
So the glitch comes back when you are using R6 in-game, right? It could help if you provided a screenshot if that is not a problem with youthe knees glitch within itself, and look super pixelated when walking or running. Well, i said above that switching to R6 in the avatar creator removes it, but once i spawn into a game (any game) it comes back.