I've seen it with White, but not on my bird!!

I think that on the white is that it is just a bit of dirt under the covering. MonoKote is my choice of covering. I did use a tad of UltraCote on this bird, the one in my avitar. MonoKote doesn't have any covering that shifts colors! Which is a HUGE BUMMMER!!!!!
Like Rollin says, I see it only on top of itself.
Don't give up on it!! They will get it right!!!