--- /buddypress/bp-groups.php (BP 1.2.6)	Thu Oct 21 13:58:22 2010
+++ /buddypress/bp-groups.php (working copy)	Thu Nov 11 12:42:57 2010
@@ -1754,7 +1754,7 @@
 	if ( groups_is_user_member( $user_id, $group_id ) )
 		return true;
 
-	if ( !$bp->groups->current_group )
+	if ( $group_id )
 		$bp->groups->current_group = new BP_Groups_Group( $group_id );
 
 	$new_member = new BP_Groups_Member;
@@ -1773,7 +1773,8 @@
 	groups_record_activity( array(
 		'action' => apply_filters( 'groups_activity_joined_group', sprintf( __( '%s joined the group %s', 'buddypress'), bp_core_get_userlink( $user_id ), '<a href="' . bp_get_group_permalink( $bp->groups->current_group ) . '">' . esc_attr( $bp->groups->current_group->name ) . '</a>' ) ),
 		'type' => 'joined_group',
-		'item_id' => $group_id
+		'item_id' => $group_id,
+		'user_id' => $user_id
 	) );
 
 	/* Modify group meta */