Hey, did you receive any official document with description of this issue from Ford service? I'm asking as I'm having the same issue probably, it would speed up the identification of the issue in the dealership I guess.
Hey, I'm struggling with this back seat rattle as well, could you elaborate what "RS" stands for? Did you lubricate the hinges where back seat folds down (those between the back part and the seat part) only? Did you also lubricate the locks that are in the seat itself?