I had something strange happen to some cookies. I decorated 3 dz cookies. I made the icing the same as I normally do. Flooded them the same as usual. I dry them in a dehydrator. I then decorated and airbrushed pearl over them. Then I let them dry again. I had some extra decorated cookies left, so bonus for me to try. When I broke the cookie in half, it was like a “top” layer of icing came off. And the icing on the cookie felt more like dust. What is going on? The only thing different is I froze the cookies prior to icing but they were thawed out real well. And I airbrushed. Any idea what might have caused this?