Got same problem for almost 2 years, dealership claims no problem but it's very obvious to me and others who drive this car!
I have another rattling noise coming from driver side door, my service manager said worked on it several times but the problem still there.
I'm not sure if these two issues will ever be solved.
I have the same noise and the dealer has tried to fix it several times now. I think it is coming from the window being loose. If you put pressure on the top of the door sill against the window the noise stops. This car has been a rattle box every since i've owned it!!!!!!!!!!!