I know this is an older post but I just recently finished my first skin and finally noticed this issue. I found an older post from Helles Belle whose solution seems to work. I don't know if the json file will have to be changed after each version update, but this does at least seem to be a temporary fix. Maybe everyone know this fix already, but just thought i would pass on what I found as I see ED has not fixed the issue yet. It might not be as noticeable in my pic below, but you can definitely tell if you use the Huey VIP skin.
https://forum.dcs.world/topic/198115-body-amp-tail-different-reflections-shiny/