That webpage has a misconfigured rel=canonical. HN replaces the URL with its canonical URL by fetching and extracting this link from the page.

  <link rel="canonical" href="www.zoraster.org/">

This value which when combined with the base URL results in the URL.

HN only does this when a new link is submitted. The item may be edited to restore its title or its URL if they have been mangled after posting.