2017 Premier purchased used in 2019 always had a nasty vibration/buzzing sound when playing some music with deep bass. Took some time and I isolated it to the driver's door panel. I was able to mitigate the offending noise by pressing on the panel about 6 inches below the lock popup. I removed the door panel yesterday and found this piece of translucent white plastic attached to the inside of the panel. It was not screwed down but held in place by three plastic buttons. Based on the shape of the piece, it looks like it was used to temporarily hold fasteners of some kind during shipping and handling of the door panel. I believe it should have been removed before the panel was installed in the vehicle. Since I removed the plastic piece the vibration is gone and I can enjoy listening to music again.
Wondering if anyone else is experiencing this annoying vibration, or has found this piece of plastic inside their door panel? BTW, there are YouTube videos showing how to remove the door panel.