The ticks don’t exist so there’s no scrubbing happening on paste, the browser only sees foo <code>example</code> bar so it copies as it would from any other webpage: it grabs plaintext as “foo example bar” (this is what gets pasted into the markdown card as that’s a plaintext editor) and the html.
If you copied content from the rich-text portion and pasted it into Atom or similar, would you expect to see ticks there?