That's not abnormal behaviour. Occasionally a DAT may be withdrawn for whatever reason or it may be simply a case that it was released to the servers late and is taking time to reach all parts of the world.
The latest release can be read here, but please note, that is an Enterprise/Business page for a different product so it more often than not at least one ahead of whatever everyone has:
The consumer product up to and including SecurityCenter version 11.x/VirusScan 15.x can be updated from that site, see: https://community.mcafee.com/docs/DOC-2155
Later versions can not as they have a different kind of engine. McAfee are working on a method for manually updating those.
Thanks Ex-Brit . . . it came through this morning at 5:00 am . . . the next one came through at 5:00 pm this evening . . . I'm still gun shy after the bad dat event a couple of weeks ago . . . appreciate your taking the time!
I don't blame you for being gun shy...LOL
All the best.