More information: I have created a Workflow to simulate the Drafts action for passing a Markdown note to Evernote. The entire workflow is comprised of the ‘Make Rich Text from Markdown’ action passed into the ‘Create New Note’ from Evernote action, and it works perfectly.
My initial thought had to do with the Markdown engine Evernote uses vs that which Drafts uses, which may be correct, but I don’t think that’s what’s going on. In the Workflow action from Evernote to create a new note, entering a title is optional. In Evernote I have the option turned on which titles the note from the first line of the text passed to it. If the Drafts action could have that ‘Title’ field made optional, we might get this to work.