BBB Logout => 404 Not Found (runs an unresolvable url)

When login out the conference using the BBB logout button, it lead to a 404 error page
It does not care about the logout address provided in the conference node settings. In my case, the address it tries to reach at logout is the following
http://91.121.117.71//see.shareontheweb.com/node/251
with 91.121.117.7 being my bbb server and see.shareontheweb.com the Drupal site (on another server) which is obviously buggy

It seems that the correct way to get out the conference is simply to leave the conference node

Possible fix:
hide the "logout" button on the BBB screen: leaving the conference url (hitting the browser back button or selecting another menu item) ends the conference participation without warning (not sure it is possible)