There's no difference between bleach (liquid chlorine) and any other type of chlorine in the pool water. It may contribute to fading the liner but not any more so than the same chlorine level (and CYA level) from any other chlorine source.

I don't see any problem with dosing bleach in the skimmer as long as there has been no dichlor or trichlor in the skimmer or filter or in a feeder. In terms of liner fading; if the water is still when bleach is added, there may be somewhat more fading below the location where bleach is added as bleach is heavier than water. By the same logic, there may be more fading where the water returns to the pool if you dose through the skimmer. Did you notice a pattern in the liner fading?