diff --git a/wp-includes/nav-menu-template.php b/wp-includes/nav-menu-template.php
index 2b24b7484..23657f7c3 100644
--- a/wp-includes/nav-menu-template.php
+++ b/wp-includes/nav-menu-template.php
@@ -426,7 +426,10 @@ function _wp_menu_item_classes_by_context( &$menu_items ) {
 					'taxonomy' == $parent_item->type &&
 					isset( $possible_taxonomy_ancestors[ $parent_item->object ] ) &&
 					in_array( $parent_item->object_id, $possible_taxonomy_ancestors[ $parent_item->object ] ) &&
-					$parent_item->object_id != $queried_object->term_id
+					(	
+						! isset( $queried_object->term_id ) ||
+						$parent_item->object_id != $queried_object->term_id
+					)
 				)
 			)
 		) {