I have had a few policies in place for a while now, every now and then
the policies dont apply.

Basically I have a policy which just changes some proxy settings and
home page settings and this is applied to a group containing all the
workstations. This has been working for a while now but for some reason
sometimes the settings just dont apply, then they will apply again.

I know that nobody can give me a straight answer on how to fix it but
where do I start tracking down this problem?

Sorry for the vagueness....