have you installed openview as windows services? If so - stop them one at a time ato keep the service up and then check the rules. Sometimes the memory fills up and the system behaves funny. Stop and start the services clears the memory.
Check if you have a lot of scheduled tasks running which can affect it also.
Yes, you can rock and roll with services by stooping and starting. But, as the SD's guardian angle, the person is supposed to give maximum uptime from the services. Again, in some type of SD-NMS integration, the tickets will not get generated during the stop & start of the service. Again, it is not the solution, it is one of the dirty workarounds.