2023 Subaru Forester Seat Belts Problems

The front passenger seat and the seat belt attached to that seat suddenly started making creaking noises as if the seatbelt or the seat itself are not properly secured whenever a passenger is sitting and seatbelt fastened while the vehicle is moving (no noise exists when the seat is empty). The noise is loudest and most prevalent when the weight of the passenger is lower, when outside temperature is cooler, when the vehicle is driven on roads that are not smooth, when the vehicle breaks and is going uphill. The vehicle has not been in any accidents and the noise appeared suddenly without any warning lights or any indications. the vehicle was bought brand new about a year ago and has just under 5000 miles. Since the noise first appeared it has been regularly occurring. The dealership has inspected the vehicle on three occasions but claims they cannot hear it or replicate it despite the fact that they agree that videos shown by the owner clearly point to this noise.