After shutdown of the old L.ROOT-SERVERS.NET the IP address formerly associated with it, the IP continued to answer requests. More informations can be found at the ICANN Blog
UPDATE: Before bothering around, if you read the ICANN Blog, you realize that the issue was fixed very shortly. The whole problem is, that the file of the root DNS servers have to be keeped up to date. This issue should be fixed by operator of resolving nameservers (usually your ISP). A goody will be, to have this fixed by the next point release of debian, but it is NOT security critical.
Thanks Thijs for make me sensible that my article may mislead people who are not reading the referenced document.
UPDATE 2: A more technical description can also be found at Renesys Blog and a discussion how it is related to debian.