mine (2012 328i 6mt) is currently at the dealer for this issue. today is day 7 its been there. dealer says bmwna is aware and have no idea whats going on. dealer says they are "checking" the car prior to returning it to me -- a 7 day check seems highly suspect. im not going to accept it back without being fixed or documentation of the issue, which they've experienced daily over the past week, and their inability to fix it as noted in the bmw service records so i can then pursue lemon laws.
dealer claims the car is fine and just has this little hiccup; i firmly disagreed. mine actually stalls about 30% of the time on cold starts. i noted to the dealer that the loaner they gave me, a 2013 328xi, doesnt have the issue so there is a clear difference between functioning and dysfunctioning cars.
Here are some vids of my car during some of these shaky startups (didnt stall these times):
In those vids, immediately after start-up clutch is released and car sits without any pedal input for the rest of the video.