[AGENT++] EngineIdTable always replaces entry, even when host is different

[KSly]

I have a scenario where the first poll of several IPs are all
successful, but on subsequent polls, the IP on which I am running the
manager always fails by SNMP time out, while all other IPs are fine.
One thing I notice is that for every snmp request, the EngineIdTable
reports that it does not know the engine id for host/port, however it
then replaces an entry for a different IP address.  This is the log
when requesting information from two different IPs (192.168.21.1 and
192.168.27.1).

Not shown here are many get requests to each IPs, all of which are
successful.  First are requests to 192.168.27.1, then to 192.168.21.1.
The first line is the final request to 192.168.21.1.

I see that the entry for 192.168.27.1 is replacing the entry for
192.168.21.1, which makes me suspicious.  Except after the polling to
192.168.27.1, the same requests go to 192.168.21.1, and the entry is
replaced again.
To be clear, the manager is running on this IP that fails (192.168.27.1).

Does anybody have any suggestion to why my subsequent requests are
failing for the IP on which I'm running the manager?

20100526.15:18:39: 5704: (2)INFO   : v3MP::EngineIdTable: replace
entry (old id) (old host) (old port) (id) (host) (port): (  80 00 1F
88 80 7C 4B 2B 3A 9B 72 CE 48             .....|K+:.r.H
), (192.168.21.1), (161), (  80 00 1F 88 80 7C 4B 2B 3A 9B 72 CE 48
         .....|K+:.r.H
), (192.168.21.1), (161)
20100526.15:18:45: 5704: (4)INFO   : v3MP::EngineIdTable: Dont know
engine id for (host) (port): (192.168.27.1), (161)
20100526.15:18:45: 5704: (5)DEBUG  : v3MP: Building message with
(SecurityEngineID) (securityName) (securityLevel) (contextEngineID)
(contextName): (), (MD5), (1), (), ()
20100526.15:18:45: 5704: (3)INFO   : v3MP: Message built OK
20100526.15:18:45: 5704: (4)DEBUG  : SNMPMessage: return value for
build message: (-1401)
20100526.15:18:45: 5704: (2)INFO   : v3MP::EngineIdTable: replace
entry (old id) (old host) (old port) (id) (host) (port): (  80 00 1F
88 80 7C 4B 2B 3A 9B 72 CE 48             .....|K+:.r.H
), (192.168.21.1), (161), (  80 00 1F 88 80 7C 4B 2B 3A 9B 72 CE 48
         .....|K+:.r.H
), (192.168.27.1), (161)
20100526.15:18:45: 5704: (5)DEBUG  : v3MP: Building message with
(SecurityEngineID) (securityName) (securityLevel) (contextEngineID)
(contextName): (  80 00 1F 88 80 7C 4B 2B 3A 9B 72 CE 48
.....|K+:.r.H
), (MD5), (2), (  80 00 1F 88 80 7C 4B 2B 3A 9B 72 CE 48
.....|K+:.r.H
), ()
20100526.15:18:45: 5704: (4)INFO   : USMTimeTable: Returning time
(engine id) (boot) (time): (  80 00 1F 88 80 7C 4B 2B 3A 9B 72 CE 48
          .....|K+:.r.H
), (154), (28786)
20100526.15:18:45: 5704: (3)INFO   : v3MP: Message built OK
20100526.15:18:45: 5704: (4)DEBUG  : SNMPMessage: return value for
build message: (-1401)
20100526.15:18:48: 5704: (6)INFO   : MsgQueue: Message timed out,
removed id from v3MP cache (rid): (10284)
20100526.15:18:48: 5704: (4)INFO   : v3MP::EngineIdTable: Dont know
engine id for (host) (port): (192.168.21.1), (161)
20100526.15:18:48: 5704: (5)DEBUG  : v3MP: Building message with
(SecurityEngineID) (securityName) (securityLevel) (contextEngineID)
(contextName): (), (MD5), (1), (), ()

Thank you.