It happens. This is pretty common. It's when they go three-plus days
old that you have to worry.
Paul Thornton wrote:
a friend called the nic yesterday to find out why an update hadn't gone
through and was told that the nic had a major database meltdown (or words
to that effect). at that point it had been 17 hours since anything had
been processed. i this is a correct report from the nic (i can't see them
lying about this :-), then i doubt the zone files got updated either.