I have noticed this on my 2009 750i. Had my service department grease them as you had done. It is a temporary fix at best. The problem is the pads have a little too much room to move or shift in the caliper. Its not really a safety issue so I doubt you will get much satisfaction from the dealer. Not many people seem to turn wrenches on this board but I was wondering if aftermarket pads or later year spec pads might fit better.