I'm a bit confused why crafting a Wind up Bismark uses an Expanse Baleen instead of the Bismark baleen.

Is this a mistake on the recipe.
Each other wind up primal uses the crafting item of the primal name.

Ifrit Horn for Wind up Ifrit.
Garuda Feather for Ifrit

and so forth.

Expanse Baleen should be tied to the more expensive items like weapons and so forth and the Bismark Baleen should gain value by being for Wind Up. It also keeps things consistent.