Sounds terribly annoying. Mine is all of 6 months old, so I can't really say - but so far so good. I have the multi-contour seats.
2014 550i xDrive MSport | Exec Package | LED | Luxury Seating | Driver Assist Plus | Cold Weather | Dynamic Handling | ACC Stop & Go | Rear Shades
2007 335i Sport Package (2007 - 2013, 89k miles)
2001 325i (2001 - 2007, 125k miles)