Symfony and FOS updates - symfony

Question

I am using symfony 2.8 and just did a composer udate on my local machine and started getting this kind of errors.
Full error (happens for both for mailer and user manager, that were working smoothly for a year...)
[Symfony\Component\DependencyInjection\Exception\InvalidArgumentException]
Unable to replace alias "fos_user.user_manager" with actual definition "my.custom_user_manager".
[Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException]
You have requested a non-existent service "my.custom_user_manager".
config.yml
fos_user:
service:
user_manager: my.custom_user_manager
mailer: my.custom_user_mailer # fos_user.mailer.twig
It happens for a custom user manager of have overriden as well. My FOS user bundle version is v2.0.0-alpha3 and has not changed since precedent version.
My service definitions used to / and look correct.
Any lead here ?
Service definitions:
// bunch of "use" here...
/**
* #DI\Service("my.custom_user_manager", public=true)
*/
class CoreUserManager extends BaseUserManager
{
/**
* #DI\InjectParams({
* "encoderFactory" = #DI\Inject("security.encoder_factory"),
* "usernameCanonicalizer" = #DI\Inject("fos_user.util.username_canonicalizer"),
* "emailCanonicalizer" = #DI\Inject("fos_user.util.email_canonicalizer"),
* "em" = #DI\Inject("doctrine.orm.entity_manager"),
* })
*/
public function __construct(
EncoderFactoryInterface $encoderFactory,
CanonicalizerInterface $usernameCanonicalizer,
CanonicalizerInterface $emailCanonicalizer,
EntityManager $em
)
{
$class = 'Medical\CoreBundle\Entity\User';
parent::__construct($encoderFactory, $usernameCanonicalizer, $emailCanonicalizer, $em, $class);
}
And the mailer
// bunch of proper "use"... here
/**
* Extends FOS mailer to send your own emails and add methods
* #DI\Service("my.custom_user_mailer", public=false)
*/
class MedicalUserMailer extends BaseMailer implements MailerInterface
{
/**
* #todo To move into settings and inject via DI
* $from = $this->getParameter('medical.core.emails')['from']; LIKE in AdminController
*/
private $from = array('support#360medics.fr' => '360 medics');
/**
* #DI\InjectParams({
* "mailer"= #DI\Inject("mailer"),
* "router"= #DI\Inject("router"),
* "templating"= #DI\Inject("templating"),
* "config"= #DI\Inject("%medical.core.emails%")
* })
*/
public function __construct(
\Swift_Mailer $mailer, UrlGeneratorInterface $router, EngineInterface $templating, array $config
)
{
parent::__construct($mailer, $router, $templating, array());
// $this->mailer = $mailer;
// $this->router = $router;
// $this->templating = $templating;
$this->config = $config;
}