In step 6, you log in with a Joomla administrator. The "Connect this site to your social network" button allows the user to connect an existing Joomla user to a Facebook account. You chose to do this when you clicked the Connect button. When you do that, it will update the 'mapping' that JFBConnect uses to say which Facebook user is connected to a Joomla user.. so the connection between a Joomla user and Facebook user you made in step 5 will be broken and the Facebook account will then be associated with the administrator Joomla user.
This is expected behavior. The ability to re-connect Facebook accounts to different user's is there as people do change accounts and do different things. In the SCLogin module, there is an option to disable reconnections. If you don't like this behavior, feel free to disable it.
Hope that makes sense,
Alex