race: Charr (tested on male, but probably affects female too)
profession: ranger/druid (probably all medium users)
The Left Oni Arm medium skin is missing its dye channels and (possibly as result?) displays corrupted textures (the Right arm doesn't have either of these issues, and as best as I can tell, neither do the other armor weights of the Left arm). I have attached an album with several examples here: https://imgur.com/a/yORL7PX
What the texture displays as seems to be random, and that includes when previewing it with nothing else equipped as well! Occasionally it will even preview with normal textures, which is why I bought the skin in the first place, unaware of the horrors about to befall me.