I always try and replicate the problem on a road as close as possible to the dealership. Then I can either show it to them or tell them on which road it is and how to reproduce it (eg drive at 40mph on that road).
With the InControl set to record every trip I can see if they at least drove on that road although I don’t know if they did the right speed etc.

 

What was the fix for the 2nd row seat rattle and the rear moonroof rattle? I have a 2018 HSE that I really love, but the rattles are sometimes enough to make me not want to drive it. I've tried driving with the 2nd row seats folded...no improvement. I have noticed that there is far more rattle if the headrests are down, so I tend to keep them up. It's difficult to pinpoint though, as some days the rattle is hardly noticeable, while other days it is constant. On the rear moonroof, I believe the source of the rattle is a rubber strip at the forward edge of the moonroof that bounces up and down like a large rubberband. Lately, I've been keeping the rear shade closed, as that tends to secure the rubber strip and keep it from rattling to some degree.
These rattles have been present from day 1.
I'd love to get these items remedied so that I can actually enjoy the vehicle.

 

I also have a rattle somewhere on my 2019 that may be the rear seat or I suppose it could be the moonroof. Hard to say. I only hear it on certain road surfaces but I do hear it several times on my commute. I haven’t tried tracking it down yet, although I did wonder if it was the folded center headrest, turns out not. I tried folding the seats and I don’t think that helped but I’ll double check.
​​​​​​​
I also thought it was the passenger door area at one point but I don’t think so, although I did find my wife had left the seatbelt twisted around so the hard plastic and metal of it was rattling against the B pillar and turning it back round the right way did at least get rid of that rattle...

I’ll try some more experimenting. I tend to drive with the moonroof shades open, so I’ll see if closing them makes any difference...
I’d like to figure out the source before raising the issue during first service.

 

Not sure what the cause was of the rear moonroof cover rattle, but they fixed that. The rattle in the moonroof area was present with the shade open.

Also not sure on the 2nd row, but I have noticed that when I have the cargo barrier in and the seat is tilted back against it the rattle goes away. It seems to be on the passenger side (US).

I have resolved some of the squeaks by adding a silicone lubricant to the door seals.

 

The moonroof rattle is precisely that rubber strip at the front of the rear moonroof. I had the same. Dealer 'reattached' it and it hasn't rattled since

However the rear seat also has a rattle (rear right hand side) which is most noticeable when there is no one in the seat. Not yet traced that one

 

My third row is what caused my rattle issue. The seat bottom bounced around in its flattened position. The other side did not. Found no way to adjust it, but I have that seat totally taken out now so problem solved. So it could be third row if installed.