Re: UsersManager.addUser returning NULL response

To clarify, after some testing...

this produces a NULL response:

Piwik_FrontController::getInstance()->init();
$request = new Piwik_API_Request("
    method=UsersManager.addUser
    &userLogin={$this->getFid()}
    &password=testing
    &email={$this->getFid()}@example.com
    &format=JSON
    &token_auth=xxxxxxxxxx
");
var_dump($request);
$response = Zend_Json::decode($request->process());

and this produces a normal response:

Piwik_FrontController::getInstance()->init();
$request = new Piwik_API_Request("
    method=UsersManager.addUser
    &userLogin={$this->getFid()}
    &password=testing
    &email={$this->getFid()}@example.com
    &format=JSON
    &token_auth=xxxxxxxxxx
");
$response = Zend_Json::decode($request->process());

both create the user successfully. Just var_dumping the request changes it's behaviour somehow? What's going on?