Hi Rob - I had this on my Lexus NX and after a lot of time, effort, unseemly words and hair pulling, I found it was the plastic cover over the seatbelt nut which secures the passenger seatbelt to the body of the car. I removed the cover and stuck a little felt with double sided tape to the inside of the cover. Guess what? Never bothered me since. I’m not saying this is the cure for the RAV4, but it might save you some time and hair pulling if it is. Good luck!