Featured then Rating Sort Order

A while go I implemented the below code snippet for Featured then rating sort order.
It seem to have stopped working. It now sort again by Featured then data published.
Example: http://www.kimberley.co.za/places/business/

https://wpgeodirectory.com/support/topic/sort-by-featured-and-rating/
// Sorting the listing page results by featured & rating.
function _gd_custom_sort_by_featured_and_rating( $orderby, $sort_by, $table ) {
if ( $sort_by == ‘is_featured_asc’ && !empty( $table ) ) {
$orderby .= ” ” . $table . “.overall_rating DESC, ” . $table . “.rating_count DESC, “;
}

return $orderby;
}
add_filter( ‘geodir_posts_order_by_sort’, ‘_gd_custom_sort_by_featured_and_rating’, 5, 3 );