Anyone else shoot this ammo supressed ?

I just bought a few boxes and it shot nice but when I got home I had a lot of unburnt powderor brass flakes in my Scorpion receiver,what causes that?

New to the suppressor world just got my stamp about a week ago and I put about 500 rounds through the Omega 9k and it's done awesome. I noticed today when I got home there was this certain spot on the end cap that has a wear on it . I don't see any baffle strikes but anyone have a clue what would ca...