Originally Posted by Weasel

It could be as simple as programming and/or resetting adaptations, could be hydrolic pressure dropping at idle causing slow reaction, could be slow moving valves/solenoids, etc. etc. etc.

It would take bringing it in to the dealer under CPO for it again, and saying you've brought it in for that a few times and no one really spent much time diagnosing it yet. Maybe have the shop forman get in it with you and show him personality what it's doing to make sure it isn't blown off and get the ball rolling.