Coupling broken at ASG after 27,000km

Hello, I’ve been driving a used purchased Hyundai i10 1.2 with ASG for a year. The car had 12,500 km when I bought it. Now the second maintenance was due with approx. 27,000 km. I explained to the dealer that I have been observing the phenomenon for a few months now, if I speed up quickly, then the speed from approx. 3000 revolutions in the same gear drops again and again or jumps, although I constantly and relatively gently accelerate. The Hyundai dealer told me after the maintenance has been done that the clutch is broken and should be replaced. Now I ask myself as a car layer: How can the clutch be due with an automated switching gear after 27,000? I was told that I would not be under the guarantee. Additional was explained to me, that can certainly happen if, for example, the ASG at the traffic light would not switch to “N” or at a lot of stop and go. So a little I had the feeling that I was being accused of a wrong operation here. However, I did not find anything in the operating manual for this purpose? Has experience?