KPackageKit updates package list too often and too aggressively

Binary package hint: kpackagekit

In "Edit Software Sources", I have unchecked 'Check for Updates' in Automatic Updates but still I always see a "Downloading repository information" icon in the system tray and on clicking it I find that its downloading repository information. Even on cancelling, it comes back again in couple of minutes. I've a limited connection so I don't want it to automatically update.
Tried to uncheck, apply, check, apply the "Check for Updates" checkbox, but it still tries to update the repository information every few minutes.

Description: Ubuntu 10.04 LTS
Release: 10.04

kpackagekit:
  Installed: 0.5.4-0ubuntu4
  Candidate: 0.5.4-0ubuntu4
  Version table:
 *** 0.5.4-0ubuntu4 0
        500 http://mirror.cse.iitk.ac.in/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: kpackagekit 0.5.4-0ubuntu4
ProcVersionSignature: Ubuntu 2.6.32-22.33-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-22-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Mon May 31 18:53:00 2010
InstallationMedia: Kubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100427)
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=en_IN
 SHELL=/bin/bash
SourcePackage: kpackagekit