Ember loading template works only on page refresh

I have in my Ember app this routes:

Router.map(function() {
    // landing page (login/register)
    this.route('home', {path: '/'});

    // authenticated pages
    this.route('webappFrame', {path: '/app'}, function() {
        this.route('feed', {path: 'feed'});
        this.route('photoDetail', {path: 'photo/detail/:id'});
    });
});

where both "feed" and "photoDetail" have a model hook that return a promise (records coming from the server); I have a loading.hbs template in the /template folder;

After a page refresh on both "feed" and "photoDetail" routes, the loading template is correctly displayed; but when navigating between the routes, it is not shown again (the outlet remains white untile the promise is resolved);

I use ember-cli 2.3.0-beta.1 (but also tried 1.13.14 stable) with ember 2.3.0; In the official ember docs is written that it should always traverse the templates tree up until it finds a loading template; can someone show me what's wrong here?