Service keeps appearing and disappearing

I’ve recently changed the settings for the CPU check on our windows servers. It used to compile 1 min, 5 min and 15 min averages, and I changed it to 5 min and 30 min. The service definition that I changed was for a hostgroup consisting of all our windows servers, except I added a host_name entry to exclude one server in particular (with a negation ‘!’).

I then added another cpu check service definition for this excluded server (which is called sunstone). However, now when I look at the service detail page in nagios, the cpu check for sunstone sometimes appears, and sometimes it isn’t there at all. There is no indication either on the page or in the logs as to why this sometimes displays and sometimes doesn’t.

Does anyone have any explanation as to why this is might be happening?

thanks,
Guy