Index: bp-activity/bp-activity-functions.php
===================================================================
--- bp-activity/bp-activity-functions.php	(revision 6251)
+++ bp-activity/bp-activity-functions.php	(working copy)
@@ -304,6 +304,11 @@
 	// Update activity meta counts
 	if ( true === bp_activity_update_meta( $activity_id, 'favorite_count', $fav_count ) ) {
 
+	    // Update the users that favorited this activity
+        $favorited_users = bp_activity_get_meta( $activity_id, 'activity_favorited_users');
+        $favorited_users[] = $user_id;
+        bp_activity_update_meta( $activity_id, 'activity_favorited_users', $favorited_users );
+
 		// Execute additional code
 		do_action( 'bp_activity_add_user_favorite', $activity_id, $user_id );