Color change ducks?

[Stoney Meadow Maple]

Brought 2 home last spring, one had blue/purple feathers, the other brown . We named them Violet and Willow respectively. Violet has changed color entirely following molt she got very bery dark and blotchy and her wing color is almost more brown, Willow on the other hand has started to have her wings turn purple… this normal?
picture 1 is willow, 2 is violet.

 

[fatty and friends]

completely normal, my (almost) 2 year old khaki hen used to be dark brown and is now almost white