A WebmasterWorld thread has one webmaster claiming Google has indexed and is listing their name server address instead of their web address in the Google search results.
He said he noticed search referrals from NS2.domain.co.uk versus his own domain name.
To me, that sounds like a server configuration issue not a Google issue. But who knows. As Tedster said in the thread, "many members here are reporting Penguin troubles, but you're the first to report anything like this."
Without knowing the domain name, it is hard to diagnosis but I find it hard to believe this is a Google bug.
Name servers tell other servers where a web address should point to. They normally do not load or redirect to a web address.
Forum discussion at WebmasterWorld.
Image credit to ShutterStock for TLD signs