Hi Maverick, 

Equal to this earlier subject: https://www.corejoomla.com/forum/support/cjforum/16591-recent-activity-showing-threads-from-secured-forum-categorie.html

It also shows that if I hit Discover "Forum members", all members are shown to everybody. I would consider it to be normal that you only can see the member list if you are logged on. 

Can you enlighten me?