Steps 1 and 3 of this recipe each call for 1/3 cup coconut milk, but the ingredient list states 1/3 cup total for the recipe. Which is correct?

Likely the latter.

It is more probable that an ingredient mistakenly got omitted from the list rather than an explicit action being erroneously added to the instructions.

This recipe is a bit of a mess anyhow as the headnote misspells the original author’s name.

This sort of sloppiness is lamentably commonplace on the Internet (not just here at Food52).

Best of luck.