Are TaskCanceledExceptions propagated to parent task?

Question

This article talks about the different behaviors regarding the propagation of the TaskCanceledException between detached and attached child tasks. But I tried by myself, it seems that for neither case would TaskCanceledException be propagated:

class Program
{

    static void Main(string[] args)
    {
        var cts = new CancellationTokenSource();
        var ct = cts.Token;
        var task = Task.Factory.StartNew(() =>
        {
            var child1 = Task.Factory.StartNew(() =>
            {
                while (true)
                {
                    ct.ThrowIfCancellationRequested();
                    Console.WriteLine("Ta!");
                    Thread.Sleep(1000);
                }
            }, ct, TaskCreationOptions.AttachedToParent, TaskScheduler.Default);

            var child2 = Task.Factory.StartNew(() =>
            {
                while (true)
                {
                    ct.ThrowIfCancellationRequested();
                    Console.WriteLine("Da!");
                    Thread.Sleep(1000);
                }
            }, ct, TaskCreationOptions.None, TaskScheduler.Default);

        }, ct);

        Console.ReadKey();
        cts.Cancel();

        Console.ReadKey();
        try
        {
            task.Wait();
        }
        catch (AggregateException ae)
        {
            foreach (var e in ae.Flatten().InnerExceptions)
            {
                Console.WriteLine(e);
            }
        }

        Console.ReadKey();
    }
}

In the code above, no AggregationException is thrown at last. And what's more, the TaskCanceledException is not propagated to UnobservedTaskException event either.

Therefore, I would like to know, if there is any difference between attached and detached child task regarding cancelling?

Thanks!