I was having some of the issues mentioned here as well. Most of our machines here are Win 7 64-bit. The Agent Procedure looks like it was executing successfully but the patch was still installed in the system. Upon further inspection, I saw some errors ("catastrophic failure") from Source WUSA in the Event Viewer > Windows Logs > Setup.
The way I was able to resolve in my situation was to:
- Run the Execute command as Step Type"Execute Shell Command".
- Enter the command line including switches (ie. %windir%\system32\wusa.exe /uninstall /kb:####### /quiet /norestart
- Select Execute as the system account.
- Check the box next to Executes the command in 64-bit command shell.
For me I was trying to uninstall KB2823324 and if you look back in the Event Viewer after running the procedure, you will see that this update needs a reboot to complete the uninstallation. Reboot and the update will be removed during the process. Hope this helps.