Switching from `gfm` to `markdown` should enable more formatting options. The extensions have been configured to be similar to `gfm` but provide some additional things, like `line_blocks` and `lists_without_preceding_blankline`s.
This was caused by creating a page before first checking whether there was any content for that page beforehand, so it would result in a rogue white page with no content.
Kristaps Jurkans