Squeak from seatbelt fabric in contact with leather seat shoulder

[docgrubs]

I have a 2015 M4 with black Merino leather and a minor but persistent noise. When the driver's side seatbelt rides over the shoulder of the driver's seat during normal driving, it makes a slight but noticeable (and annoying) friction noise all the time, right by my left ear. I am 5'9" tall and the seatbelt mechanism is, of course, not height-adjustable, so that belt rides along the seat all the time. This has been going on since shortly after I got the car 15 months ago. It seems to be related to some sticking of the seatbelt fabric over the leather; in all other cars I've had, the seatbelt moved smoothly over the seat. I've tried cleaning the belt fabric, leather care on the seat (various products), applying vinyl car or protectant to the belt to increase slickness - the noise will go away briefly then return.

I don't want to put black tape on either the seat or the belt and I don't want to mount anything on the seat shoulder which might damage the seat over time.

Anyone experienced this and managed successfully to get the leather seat and the fabric seatbelt to play well together quietly?

[JD1100]

I have this same problem. How did you fix this ?