Zabbix has snmpwalk cache for dynamic snmp indexes. Currently Zabbix checks only IP, port and OID to be sure that is the same data. But in case of SNMP context or different community cache does not work correctly.

For example, the SNMP OID for JVM heap free is:
.1.3.6.1.4.1.140.625.340.1.25
If we want that value for the admin server, I send the request to:
IP=1.1.1.1, PORT=16021, COMMUNITY=public
If we want that value for the node1 server, we send the request to same admin agent:
IP=1.1.1.1, PORT=16021, COMMUNITY=public@node1
If we want that value for the node2 server, we send the request to yet again same agent:
IP=1.1.1.1, PORT=16021, COMMUNITY=public@node2