Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 12365)
+++ wp-includes/post.php	(working copy)
@@ -3634,6 +3634,11 @@
 			break;
 		$id = $_post->ancestors[] = $ancestor;
 	}
+	
+	global $_wp_using_ext_object_cache;
+	// force a refresh of the cache in case memcached is used
+	if ( $_wp_using_ext_object_cache )
+		wp_cache_delete($_post->ID, 'posts');
 }
 
 /**