Published Variants have a visible and empty WebPreferences for Workflows who do not hide drafts

Steps to reproduce:

• set in ones own user preferences "Show hidden documents" to false
• create a new workflow, who has the option "Set Drafts to Hidden?" set to "No" (or change an existing one.
• create a new document a draft space, attach it to that workflow
• push the document through the workflow to state "published" and view the published variant

Expected behavior: In the navigation the published document is shown without children.

Actual behavior: The navigation shows one child page names "WebPreferences"
This page is empty (it does not contain any objects, especially not of type "XWiki.XWikiPreferences").