Well I'll try to say something that will make sense lol.
My neighbor once had a Cochin rooster who came from black and blue parents, but his momma had some hidden genetics for the red color. Maybe that's sorta what happened to the peachicks?
I'm not sure if there's a website for peachick colors I've seen but do you possibly have any pictures of the peachicks in question so we can help you right here on BYC?