Notification from apprequests disappearing after Facebook load

This is the code that I'm using to load the SDK:

window.fbAsyncInit = function() {
    FB.init({
        appId      : "<APP_ID>",
        status     : true,
        cookie     : true,
        xfbml      : true
    });
};

(function(d, s, id) {
    var js, fjs = d.getElementsByTagName(s)[0];
    if (d.getElementById(id)) return;
    js = d.createElement(s); js.id = id;
    js.src = "//connect.facebook.net/en_US/all.js";
    fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));

And this is called when the user clicks the invite button:

function inviteFriends(){
    FB.ui(
        {
            method: 'apprequests',
            message: 'invites you to play'
        },
        function(response){ console.log(response) } // temporary to verify
    )
}

The user experience is like described in https://developers.facebook.com/docs/concepts/requests/#ux , but when the receiver logs in the notification disappears after Facebook loading.

Searching for an answer, I found these:

Notification for facebook app requests not showing up

http://facebook.stackoverflow.com/questions/11279765/facebook-pagetab-request-dialogue-notification-shows-and-goes

http://facebook.stackoverflow.com/questions/9689927/ios-fb-request-dialogs-not-working-properly

http://facebook.stackoverflow.com/questions/9812572/facebook-sdk-javascript-request-dialog-disappearing-on-receiver-side

http://facebook.stackoverflow.com/questions/8823362/invite-friends-for-a-website-app-fb-ui-apprequests

http://facebook.stackoverflow.com/questions/10209281/handle-facebook-apprequest-notification

http://facebook.stackoverflow.com/questions/8979826/facebook-notification-from-my-app-appears-and-disappears

But:

• sandbox mode is disabled;
• the canvas app url is defined, as well as the secure canvas app url;
• the app type is defined as Web.

What am I missing?

Facebook was testing what would happen if user-to-user requests did not show up on the notifications jewel. They explain it here:

https://developers.facebook.com/bugs/532388000129311

The test has apparently concluded, and things should go back to normal soon, at least for now.