I just fixed our MX's rear hatch rattle. Apparently previous owner messed with the bump stops (there are four on the hatch and two on the base of the trunk, although those two probably need to be kept tight) and made them in such a position that 1) water was getting in, and 2) the cinch actuator didn't actuate and close the hatch fully. I moved the bump stops out a little at a time and voila, the cinch mech actuated and the rattle is gone. Still have some misalignment on the right side, so I'm going to have to matrix out the 4 different stops with dimensions and basically do a design of experiments to find the sweet spot where the hatch is flush on both sides, there are no leaks, and the cinch actuator activates.
Now I'm fighting with a random loud pop that appears to be coming from above/behind the rear right passenger captain's chair (6-seater). It's only there on rougher roads, and sounds like what I would imagine being a cable connector that slams down into the falcon wing door trim. I'm 100% unable to recreate it by tapping the areas, and have yet to have my wife drive me so I can sit back there. It's literally like a popping, but none of the trim in the entire back of the car is loose, nor does tapping all over the trim recreate the sound.