Symdaemon occasionally chewing up lots of CPU

I've had two users, both with pretty new iMacs running Mountain Lion 10.8.5 and SEP_12.1.4013.4013-1 (managed client, I have no access to server infrastructure) who have reported symdaemon chewing up lots of CPU.  One user has an admin account and was able to restart SEP.  The other does not and rebooted.

I'd appreciate any ideas about what might be the issue, possible fixes, places to look for more info (Symantec-specific logs, dump files, etc.)