Shouldn't Antivirus 11 phone home very soon after boot?

I have a Vista SP1 that I only boot weekly to update if I'm not traveling.  I'll check for the last update after 30 minutes or so and it will be days, still not having updated.  Yes, I do have automatic updates enabled and I realize it's a moot point if I just manually update but it is the first A-V I've ever had that doesn't update definitions almost immediately.  Kind of the principle of the thing!  Is there perhaps a problem?   Thank you!