`notNullValidations => false` not working??

It seems that notNullValidations => false is not working on model->save().

Detail is below.

class ModelBase extends \Phalcon\Mvc\Model
{
    public function initialize()
    {
        \Phalcon\Mvc\Model::setup([
            'notNullValidations' => false
        ]);
    }
}

use Phalcon\Validation\Validator\Email as EmailValidator;

class User extends ModelBase
{
     public function handleSaveError()
     {
         $this->handleError('save');
     }

     public function handleError($type = 'save')
     {
        if ($this->getMessages()) {
            $messages = '';
            foreach ($this->getMessages() as $message) {
                $msg = sprintf('(field: %s, message: %s)', $message->getField(), $message->getMessage());
                $messages .= '    ' . $msg . "\n";
            }
            throw new \Exception("Model $type error:" . "\n" . $messages);
        }
     }

     public function validation()
    {
        $validator = new Validation();

        $validator->rules('email', [
            new EmailValidator(array(
            )),
        ]);

        return $this->validate($validator);
    }
}

$user = User::findFirstById($userId);
$user->setEmail(null);
$user->save() or $user->handleSaveError();

then I got

2016-08-30 18:57:04 [ERROR] Model save error:
    (field: email, message: Field email must be an email address)

How do I solve this??

Anyone help!