How to reproduce it :

• define a static filter with this :

  <filters>
  	<!-- Submit a new project -->
       <filter id="submit-a-new-project" target="content"> 
          <context type="all-sites"/>
          <tags>
              <tag key="SUBMIT_A_NEW_PROJECT"/>
          </tags>
           <content-types> 
               <type id="org.ametys.web.default.Content.article"/> 
          </content-types> 
           <view>main</view> 
           <mask-orphan>false</mask-orphan>
       </filter> 
  </filters>

• create an article tagged SUBMIT_A_NEW_PROJECT,
• valid the content
• make this content orphan (delete the content of the page)

> the content does not appear into the filter until I insert this content into a page.