Report.php: Twig, convert json object into associative array

extension/Classes/Core/Report/Report.php

@@ -715,7 +715,7 @@ class Report {
         // Json decode Filter
         // E.g.: {% set obj = '["this is one", "this is two"]' | json_decode%}
         $filter = new \Twig\TwigFilter('json_decode', function ($string) {
-            return json_decode($string);
+            return json_decode($string, true);
         }, ['is_safe' => ['html']]);
         $twig->addFilter($filter);