rpm dip, jolt, and stalling from stop-start set-off. vacuum leaks?

[carl0s]

2014 m6 gran coupe, 34,000 miles in the UK.

Hi. I've had it stall twice now when tapping the throttle to start the engine and engage the clutch while sat in a drive-through. The car is stopped via ASS (stop-start). Very lightly tapping the throttle to restart the engine and engage the clutch (also known as making it creep like all other autoboxes do by default). When it stalls it puts itself into Neutral. Sometimes it's not stalled, but it's just made me nearly headbutt the windscreen.

The 'creep' has always been questionable in its engagement. I was going to run through the clutch and valve body re-learning procedure, but, I suspect there's something more going on, and that the engine might be being slightly misfuelled for that initial second after the engine starts, which is making me think of vac leaks. I'm all to familiar with BMW hose and gasket failures.

Any thoughts? I've seen a lot from the X5M people, and the corrugated crossover pipe. Weather's a bit rough today and I have to go to work as well, so I can't have a look right now and just thought I'd start making enquiries on here.

Thanks,
Carl