Originally Posted by BuraQ
Your DCT had disengaged the gear, misnomered as a slippage, until it reached a safe operating range in the power band. D mode and Sport off then an instant aggressive drive is a no no for this car
Whenever you are going to get aggressive in your driving turn the Sport button ON and S mode -(if your not acquainted with M mode)
+1 have had this happen to me when I first bought my Is. I thought it was related to my car being tuned and FBO but, I have learned this also happens bone stock as well. Like Bura Q said, when you want to get aggressive put the gearbox in sport mode and use the manual shift to put the car in the proper gear for passing power. This way you will never get slippage. There is a small learning curve when driving DCT.