diff --git a/wp-includes/post.php b/wp-includes/post.php
index 37106b3d29..55527fea85 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -3196,13 +3196,7 @@ function wp_set_post_terms( $post_id = 0, $tags = '', $taxonomy = 'post_tag', $a
 		$tags = array_unique( array_map( 'intval', $tags ) );
 	}
 
-	$r = wp_set_object_terms( $post_id, $tags, $taxonomy, $append );
-	if ( is_wp_error( $r ) )
-		return $r;
-
-	wp_cache_delete( $post_id, $taxonomy . '_relationships' );
-
-	return $r;
+	return wp_set_object_terms( $post_id, $tags, $taxonomy, $append );
 }
 
 /**
diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index 1760df24e2..1932bab383 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -2238,6 +2238,8 @@ function wp_set_object_terms($object_id, $terms, $taxonomy, $append = false) {
 				return new WP_Error( 'db_insert_error', __( 'Could not insert term relationship into the database' ), $wpdb->last_error );
 	}
 
+	wp_cache_delete( $object_id, $taxonomy . '_relationships' );
+
 	do_action('set_object_terms', $object_id, $terms, $tt_ids, $taxonomy, $append, $old_tt_ids);
 	return $tt_ids;
 }