phql resultset

I have two tables and Im using phql to join them. The resultset is Phalcon\Mvc\Model\Resultset\Complex

and I am able to set properties using

$resultset->getFirst()->tabone->setVal(2);
echo $resultset->getFirst()->tabone->getVal();

but when i use

$resultset[0]->tabone->setVal(2);
echo $resultset[0]->tabone->getVal(); //remains unchanged

the value remains unchanged, even though

get_class($aRecords[0]->tabone);

says the class is Tabone.

//these are my models
class Tabone extends \Phalcon\Mvc\Model
{
    public $id;
    public $val;
    public function columnMap() {
        return array( 'id' => 'id', 'val' => 'val' );
    }
    public function setVal($val) { $this->val = $val; }
    public function getVal() { return $this->val; }
}
class Tabtwo extends \Phalcon\Mvc\Model
{
    public $id;
    public function columnMap() {
        return array( 'id' => 'id' );
    }
}

these are the tables and values:

CREATE TABLE tabone (
    id INT(11) NOT NULL AUTO_INCREMENT,
    val INT(11) NOT NULL DEFAULT '0',
    PRIMARY KEY (id)
);
CREATE TABLE tabtwo (
    id INT(11) NOT NULL,
    PRIMARY KEY (id)
);
INSERT INTO tabone (id, val) VALUES (1, 1);
INSERT INTO tabtwo (id) VALUES (1);

this is what i am doing in the controller

        $oBuilder = $this->modelsManager->createBuilder();
        $oBuilder->columns(['Tabone.*', 'Tabtwo.*']);
        $oBuilder->from(['Tabone']);
        $oBuilder->join('Tabtwo', 'Tabone.id = Tabtwo.id');
        $oBuilder->where('Tabone.id = 1');
        $aRecords = $oBuilder->getQuery()->execute();

        //this doesnt work as expected
        $aRecords[0]->tabone->setVal(2);
        echo "2 != ".$aRecords[0]->tabone->getVal()."<br>";

        echo get_class($aRecords[0]->tabone).'<br>';

        //this works as expected
        $aRecords->getFirst()->tabone->setVal(2);
        echo "2 == ".$aRecords->getFirst()->tabone->getVal()."<br>";

Why are the setters/getters no working when using [0] ? am i doing something i shouldn't ? ...