diff --git a/core/lib/Drupal/Component/Serialization/YamlSymfony.php b/core/lib/Drupal/Component/Serialization/YamlSymfony.php
index 639f5f8..390178f 100644
--- a/core/lib/Drupal/Component/Serialization/YamlSymfony.php
+++ b/core/lib/Drupal/Component/Serialization/YamlSymfony.php
@@ -19,7 +19,7 @@ public static function encode($data) {
     try {
       $yaml = new Dumper();
       $yaml->setIndentation(2);
-      return $yaml->dump($data, PHP_INT_MAX, 0);
+      return $yaml->dump($data, PHP_INT_MAX, 0, SymfonyYaml::DUMP_EXCEPTION_ON_INVALID_TYPE);
     }
     catch (\Exception $e) {
       throw new InvalidDataTypeException($e->getMessage(), $e->getCode(), $e);