Check the systems...
I have seen the SEPM report stale data for this piece, so i would Remotely connect VIA Computer Management to one of those systems, services, Symantec Endpoint...etc and see if RTVSCAN (Realtime) is running. Next check to make sure that its set to automatic, also make sure the Firewall/ICS service is off if using SEPs NTP. The windows firewall can cause issues with reporting to the SEPM, meaning it might show rtvscan is NOT reporting in as running BUT it really is.