I noticed on the Network User page that the Community User has starred a question on the Skeptics site.
So why does the community user have a starred post? Does the community user own stars from deleted users? What criteria must be met for the community user to own a star on a post?
This is not a duplicate of What can cause the Community user to have favorite questions? because that was a site-specific problem for SharePoint; it does not explain the issue on Skeptics.