GM had a press release about this, and they stated "It is unfortunate that this incident happened. Many factors contributed, including weather and track conditions. "
Yes, those were excellent conditions, it was sunny, the track was dry, the temp was around 70, and those... are perfect conditions for nothing to occur that is surprising or unexpected.
GM also released another press statement about the guy who wrecked their Corvette:
"Reuss is a certified industry pool test driver on the North Course of the Nürburgring track in Germany. He also created and led the GM Performance Division in 2001, when he was responsible for GM racing vehicles, as well as production versions of Chevrolet SS models and the Cadillac V-Series."
So, track conditions were perfect, and the driver was experienced and a pro at the Nürburgring.
What could possibly be the problem then, when you've got a great day, and a great driver, and a great car?