Phalcon 1.2 - Paginator\QueryBuilder returns no results

Hello Phalcons.

Before posting an Issue on github I would like to check if I am missing something:

When using the following code

$builder = $this->modelsManager->createBuilder();
$builder->from('Contacts');
$paginator = new \Phalcon\Paginator\Adapter\QueryBuilder(
    array(
        "builder" => $builder,
        "limit"=> 10,
        "page" => 1
    )
);
$result = $paginator->getPaginate();

$result is a stdClass with an empty items property. The query send to the DBMS is correct and all other properties seem to be set correctly.

What do I have to do to make it work?