Different appearances of hybrids of Red-crested Pochards x Mallard

Photos of two different hybrids of Red-crested Pochard / Kolbenente (Netta rufina) x Mallard / Stockente (Anas platyrhynchos), taken in the same place (Rheindelta, Austria), 18 years apart in May 2005 and November 2023. This hybrid combination occurs quite regularly in parts of Austria, Switzerland and Germany (see references below).

May 2005, male or female „intersex“ (?) due to dark bill:
This bird was diving like a Red-crested Pochard (contra Glutz von Blotzheim 2019).

November 2023, male:

References:
Glutz von Blotzheim, U.N. (2019)
Lehmhus, J (2011): Beitrag zur Identifikation von Kolbenentenhybriden. AVES Braunschweig 4: 21.
Möller, (2011)