I have worn my XDm in a Theis Hybrid holster almost daily for over a couple of years now. I have noticed over the past several months that the black nitride/Melonite coating is coming off and being absorbed into parts of the leather holster. The coating is notably lighter in the corresponding areas on the slide. It hasn't affected the gun other than the color, but I am curious to know if this is normal. The side of the slide that contacts the kydex is unaffected by this issue. I know that I have acidic sweat, and as such, I can't wear anything but solid stainless steel or gold jewelry. Also, if it's of any value, I have used nothing but Froglube on the firearm for about eighteen months or more. I don't know if that has anything to do with it or not. This issue doesn't bother me much. I feel the look adds a certain level of character to the gun, but I am curious to know what is causing it and if it is normal.