Don't completely rely on dig, as you might be obtaining a cached DNS response. DNS servers usually cache responses for a certain time. You can try using dig along with the +trace option to see where the query is going through, or even querying directly the authoritative server for some of the domains and see the result for debugging purposes.
Another idea: Is your environment chrooted? Maybe it's a resolv.conf misconfiguration inside your chroot jail. Regards, Nicolás
