Ok, this is the second time I get a contrarious behaviour with Phalcon, and it's strange (the first one was when validating the other days).
Explain me why this works with one model, and why not with two:
public function get()
{
    return Model::find();
}
Because in the second I need to do this:
public function get()
{
    $models = array();
    foreach (Model::find() as $model)
    {
        $models[] = $model;
    }
    return $models;
}