LiveUpdate Periodically Loads All Virus Defs - Over 500MB

I have several PCs with NIS 2012 (preferred version) installed with one Vista and four Windows 7 OS. All OS are 64-bit except one Windows 7 32-bit, my problem PC here. About every 3-4 weeks, I get the full download of the 32-bit 2012 Virus Defs, currently over 500MB because I’m not using Smart Defs on any of my PCs. This has been going on for 6-8 months. I update my Win7 32-bit every 2-3 days at most and the updates NEVER fail. None of my 64-bit PCs do this. I do update the 32-bit PC on Dialup Internet always except when I need 500+MB. The others are normally updated on hi-speed Broadband. Could this be a LiveUpdate 32-bit bug? Any suggestions? Should I try updating my 32-bit with hi-speed Broadband only?