I noticed that as I was walking by my armor stand, the leather pants' legs were white or grey for some reason. The first time I obtained the leather pants, they weren't dyed, but they were enchanted with Blast Protection IV. I thought the enchantment caused the pants to look like that, so I disenchanted it with the new grindstone. When I placed them back, the legs were still that color. As you can see in the image provided, the hip part of the pants was still undyed, and has an obvious contrast with its white or grey legs.