SUS Client Problems

Hi,

On some machines on my network (particularly newly
deployed machines that were imaged) the client users are
prompted to reboot their machines because of new updates
that have been pulled down via SUS. I have it set to
install at noon, and not give the user an option to
choose "no". The problem is that on some machines, the
users are prompted to reboot to complete patch installs
everyday, obviously there aren't new patches on the SUS
server everyday. If I re-apply the AU settings it
resolves the problem 95% of the time, other times I have
to re-apply the settings, clear the WUTemp folder, and
install any updates manually from the windows update site
on the client machines. I would like to know why this is
happening, it's kinda strange that it's only on some
machines. Thanks!