How to reproduce it :

• you have to have a workspace configured with documents
• The user used to test have to have the rights to the workspace and to the current site
• add a search engin service into a page with follow parameters :
  • Search by content type : all
  • Choice of type : Using a filter on results
  • multisite checked
  • Expand the search to workspaces checked
  • Display results on this page, under search criteria
• Launch a search that you are sure that only documents of the workspace whould be returned

> There is results but the pagination display that : Results 1 to 1 of 0
and the number of results is 0.