Black powder surfacing on DLC plating

[hermit dave]

I have all three of Cold Steel's Warcraft Tantos. I found that the Medium and XL have a black powder forming on the surface of the DLC coating. I wiped it off, only to find it has returned later. Does anyone know what this is? The large does not do this and I have never seen this on my other DLC coated knives. It's a jet black very fine powder.

 

[Korean Hog]

Never heard of this either.
Curious to see what people have to say??