Property is not flushed - symfony

Question

I call a service in a controller:
$this->getContainer()->get('pro_convocation')->sendDelegationEmails();
Here it is the method executed with the service:
function sendDelegationEmails()
{
foreach ($this->getRepository()->findWithPendingDelegationsEmail(1) as $convocation) {
if (! $convocation->delegationsEmailCanBeSent()) continue;
$this->sendDelegationsEmails($convocation);
$convocation->_setDelegationsEmailIsSent(); //<--- it is not saved
$this->save($convocation);
}
}
and the other used methods in the same class:
/**
* #return \Pro\ConvocationBundle\Entity\ConvocationRepository
*/
private function getRepository()
{
return $this->get('doctrine')->getRepository('ProConvocationBundle:Convocation');
}
function save(ConvocationEntity $convocation)
{
$this->getEntityManager()->persist($convocation);
$this->getEntityManager()->flush();
}
function sendDefinitiveMinute(ConvocationEntity $convocation)
{
foreach ($convocation->getCommunity()->getMembers() as $user) {
$this->get('pro.notifications')->send(Notification::create()
...
->setBody($this->get('templating')->render(
'ProConvocationBundle:Convocation:definitive-minute.html.twig',
array(
'convocation' => $convocation,
'convocationIsOrdinary' => $this->get('pro_convocation.ordinariness')->isOrdinary($convocation),
'user' => $user
)
))
);
}
}
EDIT: The send method:
function send(Notification $notification)
{
if (! $notification->getRecipient()) throw new \Exception("Recipient not set");
if (! $notification->getRecipient()->getEmail()) {
$this->logger->info(sprintf(
"Notification \"%s\" ignored as recipient %s has no email",
$notification->getSubject(), $notification->getRecipient()));
return;
}
// Ignore notifications to the own author
if ($notification->getAuthor() === $notification->getRecipient()) {
$this->logger->info(sprintf(
"Notification ignored as recipient is the author (%s)",
$notification->getRecipient()));
return;
}
$em = $this->doctrine->getManager();
$em->persist($notification);
$em->flush();
if ($this->notificationHasToBeMailed($notification)) {
$this->mail($notification);
$this->logger->info("Notification mailed to {$notification->getRecipient()}");
}
}
END EDIT
The _setDelegationsEmailIsSent method and delegationsEmailIsSent property in the Convocation entity:
/**
* #ORM\Column(type="boolean", name="delegations_email_is_sent")
* #Constraints\NotNull
*/
private $delegationsEmailIsSent = false;
/**
* #internal
* #see \Pro\ConvocationBundle\Convocation::sendDelegationsEmails()
*/
function _setDelegationsEmailIsSent()
{
$this->delegationsEmailIsSent = true;
}
The problem is that delegations_email_is_sent in the database is not changing to true when executing the sendDelegationEmails method in a controller. I've tried several changes without success. It seems to be related to flush method, but I don't find the issue.