I remember reading somewhere (was probably kingsnake or ralph davis's forums) that when mixed with another gene the super form of the cinnamon/black pastel doesn't have the duck bill problem -- regardless of line. It only seems to show up in plain old super cinnamons or super black pastels. Maybe someone else has more information on this, or even better, some first hand experience.

Albey, do your regular super cinnamons get the duck bill?