And they've never produced any anery babies at all? The first thought I had was a chimera, but if there's no anery gene in the dad at all, that becomes extremely unlikely.
Next is paradoxing, that she had a specific subset of cells during develop 'break' the ability to make the red pigment as well.
After that there's physical abnormalities; Rich has produced babies with white patches that had association with spinal kinks.
There's also the chance it's something new. Definitely keep it.