0.02% is not common. There seems to be a group of people some who don't even own a C8 that make loud statements that C8s have "very common catastrophic issues" such as engine failure from cylinder deactivation, DCT failure if you look at your car the wrong way, the HTC roof failure that happens to everybody on the US forum. There are also people who will claim that C8s have horrible body gaps, paint quality, and dealer experience. Hell there are even few people who will tell you that C8 overheat under normal conditions and require extra fans installed so they don't burst into flames.
Thing with the internet is you get what you search for: there are 100,000 posts that the C8 has been problem free ownership experience, but if you search for "C8 HTC failure" or "C8 DCT failure" you will get 100s of posts that report those issues and 1000s of posts of people repeating those issues without experiencing them on their own cars.
now, OP reported that he has this HTC failure twice of 2 different C8s, and this should be investigated closer. OP i wonder how often you operate your HTC while the car is moving?