Listed where? In the Joomla backend, or in a component? This should not be the case, and is the first we've heard of this issue. If there's any more information you can provide, that'd be helpful.
Also, what setting do you have JFBConnect "Create New Joomla Users" set as? It shouldn't matter, but will help us investigate.
Bug: FBConnect Users not listed as online when logged in
