Strange Issue with Throttling

[arielbh]

I've a strange issue.
I'm creating an observable using the following code.

        var contact = _bandService.Sensors.Contact;
        var heartBeat = _bandService.Sensors.HeartRate.OnlyWhenWorn(contact);
        FakeCondition = heartBeat.Where(h => h.HeartRate > heartRate - 20 & h.Quality == HeartRateQuality.Locked)
            .Select(h => new BandState {HeartRate = h.HeartRate, Status = "aaa"});

I verified that I'm reaching the Select statement.

Now on the consumer side I'm subscribing to the observable like this.
Everything is working as expected.
FakeCondition.ObserveOnDispatcher().Subscribe(s =>
{
//DoSomething();
});
but if I had a Throttle construct, I will never receive any calls. Any ideas?
FakeCondition.Throttle(TimeSpan.FromMinutes(5)).ObserveOnDispatcher().Subscribe(s =>
{
//DoSomething();
});

Ariel