I've got the same sound on my 2017 Limited. What's crazy is my partner's 2017 Limited does not make the sound. It's annoying, but I'm so used to it anymore, I just let it go. I don't want to play the whole game with the dealer not hearing it, when it's a clear as day. I did that with my passenger front door, as it rattles when music is turned up... no one heard anything, but they said my drivers door woofer was blown... I know it wasn't, but that damned rattle is still there.