Index: wp-includes/meta.php
===================================================================
--- wp-includes/meta.php	(revision 15687)
+++ wp-includes/meta.php	(working copy)
@@ -235,7 +235,7 @@
 	}
 
 	if ( ! $meta_key )
-		return $meta_cache;
+		return array_map( 'maybe_unserialize', $meta_cache );
 
 	if ( isset($meta_cache[$meta_key]) ) {
 		if ( $single )