When you use the EPUB output (pandoc) the file that is created doesn’t honor any YAML properties that you set for the document. For example if I go to the File Properties and give the document a title and author they won’t be passed to the epub output. If I manually add it to the YAML properties tab or directly to the document it still doesn’t pass the information to the epub output.
title: My EPUB Title
author: Willy Wonky