The Display Macro generates invalid HTML when used in-line

1. Create a Page
2. In wiki editor insert a text followed on a new line by a display reference macro
   Example:

   !
   {{display reference="Sandbox.TestPage3"/}}
   

3. Save (everything should be ok, content rendered correctly)
4. Edit with CK Editor
5. Resave

Result: Rendered content is duplicated inside the page. (see screenshots)