Index: wp-includes/class-wp-term-query.php
===================================================================
--- wp-includes/class-wp-term-query.php	(revision 41170)
+++ wp-includes/class-wp-term-query.php	(working copy)
@@ -654,6 +654,10 @@
 			$where = "WHERE $where";
 		}
 
+		if ( isset( $args['object_ids'] ) && empty( $distinct ) ) {
+			$distinct = 'DISTINCT';
+		}
+
 		$this->sql_clauses['select']  = "SELECT $distinct $fields";
 		$this->sql_clauses['from']    = "FROM $wpdb->terms AS t $join";
 		$this->sql_clauses['orderby'] = $orderby ? "$orderby $order" : '';