HTML page for /help/user/markdown.md displays large portions of raw source markdown instead of being rendered as HTML

On GitLab 17.8.2, the /help/user/markdown.md page is broken and some paragraphs are not properly rendered to HTML and the raw markdown is displayed instead.

E.g. in the capture below, the literal inside +} should be in a pre-formatted section and the ## Headings should be outside this section and rendered as a HTML H2 :

Large portions of this page are displayed as raw markdown instead of being properly rendered as HTML.

The rendering of his help page is broken on both EE and CE.