Steps to reproduce:

upgrade to 6.4.12 turns the server or proxy to intermittently or randomly mark SNMP traps as unmatched in the logs and those SNMP traps are missed. It worked before with the hosts for months and years. 

Nothing new was introduced. Just upgrade caused this.

Result:
See screenshot...
See log file...
See memory dump...
Expected:
See screenshot....
See attached patch file...