If you have markdown headings in the .Inner
and you want them to show up in a table of contents you can try something like this:
## Heading
{{ printf "<div clas=\"markdownify\">" | htmlUnescape | safeHTML }}
{{ .Inner }}
{{ printf "</div>" | htmlUnescape | safeHTML }}
Thank you @zwbetz for this work around.
See: Shortcode - markdown vs html vs table of content