I too believe the issue may be resolved by breeding unrelated animals.

I remember back when I was researching both Cinnys & Black Pastels, the trait was first noted in Cinnys. Then I saw the 1st Sliver Bullet & knew I had to get in on the Black Pastels. I liked the funky patterns on them & how dark they are.

I contacted Chris @ GCR about an outstanding male they had & after speaking with him, he confirmed the animal was from the same WC group as Ian G's line. After I got my boy, I got an unrelated female & this year they produced this girl:



You'll note she has white on the sides of her face but no "duck bill":