Try one last thing before going to the dealer for resolution - clear out the adaptive throttle and transmission settings.

With the car in park and the engine shut off, turn the ignition to position 1 and step on the accelerator pedal for 30 seconds, then release it. The adaptive settings should be erased. Drive it as you normally would, but keep in mind you're still in the break-in stage.

This may or may not help but it's worth a shot. From reading the threads supplied by TrueX5er, it might be something more. If it helps, that's great, if not, good luck...