facebook.com delegation

[Jeff Wark]

We are currently having some difficulty resolving facebook.com.  Restarts of our nameservers solve the problem for a short time, 
but it crops up again.

It seems that 'www.facebook.com' and 'login.facebook.com' are delegated zones and the delegation is not set up correctly.  The 
name servers for 'www.facebook.com' and 'login.facebook.com' do not return NS records.  Perhaps I am checking something 
incorrectly, its been a long day.

Can anyone confirm or deny these delegation problems?  If confirmed, what kind of problems could be expected?

Thank for taking a look.

Jeff Wark
TBayTel Internet