This was supposedly fixed in the latest version of SEP 14, which is RU1. If it's still occurring you're best off getting a case opened up so they can do root cause analysis.
http://www.symantec.com/docs/TECH247345
http://www.symantec.com/docs/TECH247996
This may also apply:
http://www.symantec.com/docs/TECH236543
Support will likely need process and/or memory dumps as well as advanced logs generated by SymDiag.
-Brian