At the moment, there's not a whole lot of information about this subject. Most users complain about defective RTX 2080 Ti Founders Edition cards, but it could be because this card has been available in volume for a longer time than the custom cards. There's some speculation that there could be an issue with the GDDR6 memory, or perhaps even with the Turing GPU. Particularly worrying are posts from users who have been send a replacement card, and are still experiencing issues.
Tom's Hardware asked NVIDIA for a response and got to hear that it's business as usual:
Nvidia, for its part, has treated these complaints like business as usual. The company told us that "it's not an increasing number of users" affected by this problem, saying "it's not broad." It added that "we are working with each user individually like we do always."