Index: src/wp-includes/formatting.php
===================================================================
--- src/wp-includes/formatting.php	(revision 46962)
+++ src/wp-includes/formatting.php	(working copy)
@@ -4844,6 +4844,9 @@
 	} elseif ( is_object( $value ) ) {
 		$object_vars = get_object_vars( $value );
 		foreach ( $object_vars as $property_name => $property_value ) {
+			if (ord($property_name) === 0) {
+				continue;
+			}
 			$value->$property_name = map_deep( $property_value, $callback );
 		}
 	} else {