Thank you for this extension.
I encountered a bug where if the user logs out, a later log in action fails due to some user data persisting. I fixed it by changing this:
if ( strcmp( $capitalizedUsername, $wgRequest->getCookie( 'UserName' ) ) == 0 ) return false; if ( strcmp( $capitalizedUsername, $wgRequest->getSessionData( 'wsUserName' ) ) == 0 ) return false;
into this:
if ($wgUser->isLoggedIn()) return false;