for me this was brake switch failure
I had that happen once, just like you describe. I had noticed some subtle throttle hestiations previously, but then the throttle just cut out, without stalling, and this lasted for a couple seconds before kicking-in. Immeadiatly after that occurance, my brake lights were on constantly (even when the car was off), and acceleration was weird to say the least, it sort of hesitated a bit then kicked-in harshly, but I was able to drive the car to the dealer. Turned out the brake switch was bad, which makes DSG think you have the brakes on and thus it acts stangely. The dealer replaced the switch and it has been fine ever since.