I happens with mine too. It also shifts the weight forward a little bit when I apply the hand brake and turn off the car. I am planning to ask the dealer to take a look at it during my next service.

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2008 BMW X5 4.8i/Space Gray Metallic/Gray Nevada Leather/Dark Burl Walnut Wood Trim/Sport Package/Premium Package/Cold Weather Package/Technology Package/Ipod and USB Adapter/Running Boards/Satellite Radio

Retired: 2004 325i Orient Blue/Sand Leather/Wood Trim/SMG/Premium/Sport/Navigation/Xenon/Premium Sound