Who has been receiving large LiveUpdates?

A few months ago, I began receiving unusually huge (250-350MB) LiveUpdates from Norton.  Because I update my anti-virus manually within 24-48 hours, the size of the updates should have been 5-10MB.  Additionally, the automatic LU always fails to install any updates.  When I contacted Norton about the problem, a representative instructed me to fix the problem by installing a Norton Intelligent Updater.  Unfortunately, the updater did not solve the problem.  Thus, I uninstalled the Norton software & re-installed it again.  The manual LU’s were back to its usual size of 5-10MB & the automatic LU’s worked fine.  However, the problem with the LU’s re-appeared again a couple of days later. 

If you use any Norton software for your device, have you been receiving unusually large LU’s?  If so, do you know the reason for these huge updates?  What did you do to fix the problem?

Please note that this problem affected my old Windows XP PC & my new one which is a Dell Inspiron with a Windows 8.1 OS.

My NIS is Version 21.0.0.100