F82 M4 (2016) grinding noise from standing start

[andyf82]

Hello,

I have a BMW F82 (M4) with dct (2016).
I have noticed over the past few weeks that when i first start up the car and reverse it off the driveway, as soon as i put my foot on the accelerator to move away, for the first 5 seconds or so i hear a rather unnerving grinding noise from what appears to be the transmission - def under the car . There is also some small vibration - almost like im going over gravel. However, once i get through this from the initial start off, it disappears and the car drives perfectly. Its under warranty and is going in in early Jan_23 to a dealer to investigate. Ive searched all over and cant find anything. I have noticed that it sometimes does it when the engine is warm too. The car drives fine otherwise. No alarms or notifications on the car either.
It does it when in drive mode and when i use the flappy paddles in first. Some people saying its normal? I cant believe this really as it didnt do it for first 6-7 months of ownership. What do you think?
Thanks,
Andy