Message (from message stack) not translated into the preferred language of the recipient

Question

Here is a code which can be pasted into devel/php (run php code) if the message template new_user_register exists with a user reference field called field_user_reference

This message should be sent when a new user register himself (But this has no link with my problem as the code can be run outside... I provide this information just to give some context)

$id=127;
$account=\Drupal\user\Entity\User::load($id);
$message=\Drupal\message\Entity\Message::create([
    'template' => 'new_user_register',
    'uid' => $id
]);
$message->set('field_user_reference', $account);
$message->save();

$subscribers = \Drupal::service('message_subscribe.subscribers');
$notify_options = [];
$subscribe_options = [
    'notify message owner' => TRUE,
    'notify blocked users'=>TRUE, //new user is blocked
    'entity access'=>FALSE, //new user don't have access (blocked)
    'uids' => [new \Drupal\message_subscribe\Subscribers\DeliveryCandidate(['subscribe_user'], ['email'], $id)],
];

$subscribers->sendMessage($account, $message,$notify_options,$subscribe_options);

Even if the template is translated, the user 127 will not receive the message in his preferred language but in the site default language.

Is it a bug or am I missing something?

Answer 1

I have made a path here: https://www.drupal.org/project/message_notify/issues/2965975#comment-13559090

Feel free to test it and report any problem