Squeaks and rattles are covered under warranty. But if you don't want to mess with the dealer, maybe shim thin cuts of thin adhesive foam between the panels. I use to do that for interior squeaks and rattles on various cars and it worked great.
Not necessarily this, but it's what I'm talking about.
https://www.amazon.com/Pres-P8225RL0...p/B01G382DX4/r