I have installed the action and the shortcut to test this out.
When I ran it as is, with three drafts selected, it added the first draft to Day One and failed trying to add the second draft.
I set the wait for response option for the shortcut step and tried the same test again. This time it transferred all of the selected drafts to Day One.
I can therefore confirm it is working just fine for me with the revision I had suggested previously.