Index: wp-includes/general-template.php
===================================================================
--- wp-includes/general-template.php	(revision 5143)
+++ wp-includes/general-template.php	(working copy)
@@ -192,7 +192,7 @@
 	// If there's a month
 	if ( !empty($m) ) {
 		$my_year = substr($m, 0, 4);
-		$my_month = $wp_locale->get_month($m);
+		$my_month = $wp_locale->get_month(substr($m, 4, 2));
 		$title = "$my_year $sep $my_month";
 	}