Php catchable fatal error: object of class WP_term could not be converted to string in wp-includes/taxonomy.php on line 2334

PHP Catchable fatal error:  Object of class WP_Term could not be converted to string in wp-includes/taxonomy.php on line 2334

if ( $delete_tt_ids ) {
			$in_delete_tt_ids = "'" . implode( "', '", $delete_tt_ids ) . "'";
			$delete_term_ids = $wpdb->get_col( $wpdb->prepare( "SELECT tt.term_id FROM $wpdb->term_taxonomy AS tt WHERE tt.taxonomy = %s AND tt.term_taxonomy_id IN ($in_delete_tt_ids)", $taxonomy ) );
			$delete_term_ids = array_map( 'intval', $delete_term_ids );