update

api/v3/FormProcessorInstance/Create.php

@@ -61,7 +61,7 @@ function _civicrm_api3_form_processor_instance_create_spec(&$spec) {
   $spec['permission'] = array(
     'title' => E::ts('Permission'),
     'type' => CRM_Utils_Type::T_STRING,
-    'api.required' => true
+    'api.required' => false
   );
 }