Symfony3 entity property not being updated through OneToMany association method - doctrine-orm

Question

I have the following classes:
class Pedido
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
protected $id;
/**
* #var \DateTime
*
* #ORM\Column(name="fin", type="datetime", nullable=true)
*/
private $fin;
/**
* #ORM\OneToMany(targetEntity="Estado", mappedBy="pedido", cascade={"persist","remove"})
*/
protected $estados;
public function addEstado(\AppBundle\Entity\Estado $estado)
{
$estado->setPedido($this);
$this->estados[] = $estado;
$this->estado = $estado->getEstado();
return $this;
}
}
class Estado
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var string
*
* #ORM\Column(name="estado", type="string", length=255)
*/
private $estado;
/**
* #ORM\ManyToOne(targetEntity="Pedido", inversedBy="estados")
*/
protected $pedido;
}
But when I call:
$pedido = $em->getRepository('AppBundle:Pedido')->find(18);
$estado = new Estado;
$estado->setEstado('New Estado');
$pedido->addEstado($estado);
$em->flush();
The new Estado entity is persisted correctly, but Pedido remains with estado "Old Estado".
I have dumped $pedido pre and post flush and getEstado returns "New Estado", but in the database remains as "Old Estado".
Weird thing is that if I call:
$pedidos = $em->getRepository('AppBundle:Pedido')->findAll();
foreach($pedidos as $pedido)
{
$estado = new Estado;
$estado->setEstado('New Estado');
$pedido->addEstado($estado);
}
$em->flush();
First $pedido remains with estado "Old Estado", but all the others succesfully get changed to "New Estado".
Any ideas?
UPDATE:
I have a PostPersist method that on estado = "Caducado" calls:
$pedido->setFin(new \DateTime);
That's what making the first $pedido estado property to stay the same, but can't find the reason why

Answer 1

Changed:
$pedido->setFin(new \DateTime);
From PostPersist to PrePersist and problem solved, if anyone knows the explanation behind that, please add it below.