JSX (SSX too?) gets executed twice if set to "On this page or on demand" and included manually

1. Create a test document with just a JSX include:

   {{velocity}}
   $xwiki.jsx.use($doc.fullName)
   {{/velocity}}
   

2. Then add a simple JSX object:

   var times = window.times || 0;
   times++;
   alert('JSX executed! ' + times);
   

   ...leave the default option to "On this page or on demand"

3. Save&View the page (make sure to refresh the browser cache).
4. The javascript gets executed twice.

Not sure about SSX and how they are handled, but javascripts get included twice in the output HTML's HEAD section.

This issue looks a lot like XWIKI-7702.