There is a Linux server that sends SNMP trap.

This SNMP trap is received by snmptrapd, processed by /usr/bin/zabbix_trap_receiver.pl and written into /run/zabbix/zabbix_traps.tmp.

Zabbix server is configured to read /run/zabbix/zabbix_traps.tmp.

I can see an SNMP trap in /run/zabbix/zabbix_traps.tmp, but I don't see this trap in latest data, in Zabbix GUI.

Important notice - SNMP traps are visible if I restart Zabbix server service and stop being visible in the GUI in a week, approximately.

If I look closely, I notice that SNMP traps are updated in Zabbix GUI, but very slowly.

For example, it is 12:24 pm now and if I refresh latest data page, I see traps several hours old appearing at the moment:

This is not related to some specific trap, but multiple SNMP traps.

Next. We have two similar Linux machines and both of them are sending similar traps, but currently this issue is present only with one of them:

Example #1. This trap is not visible in Zabbix:

Host IP is 172.26.0.157

SNMP trap message in zabbix_traps.tmp:

_{09:05:24 2021/06/17 ZBXTRAP 172.26.0.157
DISMAN-EVENT-MIB::sysUpTimeInstance type=67 value=Timeticks: (499104298) 57 days, 18:24:02.98
SNMPv2-MIB::snmpTrapOID.0 type=6 value=OID: SNMPv2-SMI::enterprises.50126.10.0.2.2
SNMPv2-SMI::enterprises.50126.10.0.1.9.11 type=65 value=Counter32: 283876
SNMPv2-SMI::enterprises.50126.10.0.1.9.12 type=65 value=Counter32: 740678
SNMPv2-SMI::enterprises.50126.10.0.1.9.0 type=4 value=STRING: "Cleared"
SNMPv2-SMI::enterprises.50126.10.0.1.8.0 type=4 value=STRING: "Btc HE (3/3)"
SNMPv2-SMI::enterprises.50126.10.0.1.1.0 type=4 value=STRING: "TV channel (udp://239.31.1.82:1234)"
SNMPv2-SMI::enterprises.50126.10.0.1.2.0 type=4 value=STRING: "TR_101_290_ContinutyCount"
SNMPv2-SMI::enterprises.50126.10.0.1.10.0 type=4 value=STRING: "warning"
SNMPv2-SMI::enterprises.50126.10.0.1.3.0 type=4 value=Hex-STRING: 07 E5 06 11 08 37 15 00 2B 03 00
SNMPv2-SMI::enterprises.50126.10.0.1.4.0 type=4 value=Hex-STRING: 07 E5 06 11 09 05 12 00 2B 03 00
SNMPv2-SMI::enterprises.50126.10.0.1.6.0 type=4 value=Hex-STRING: 07 E5 06 11 09 05 17 00 2B 03 00}

Example #2. This trap is visible in Zabbix:

Host IP is 172.26.0.158

SNMP trap message in zabbix_traps.tmp:

_{11:46:34 2021/06/17 ZBXTRAP 172.26.0.158
DISMAN-EVENT-MIB::sysUpTimeInstance type=67 value=Timeticks: (231565404) 26 days, 19:14:14.04
SNMPv2-MIB::snmpTrapOID.0 type=6 value=OID: SNMPv2-SMI::enterprises.50126.10.0.2.2
SNMPv2-SMI::enterprises.50126.10.0.1.9.11 type=65 value=Counter32: 232210
SNMPv2-SMI::enterprises.50126.10.0.1.9.12 type=65 value=Counter32: 741210
SNMPv2-SMI::enterprises.50126.10.0.1.9.0 type=4 value=STRING: "Cleared"
SNMPv2-SMI::enterprises.50126.10.0.1.8.0 type=4 value=STRING: "Btc HE (1/3)"
SNMPv2-SMI::enterprises.50126.10.0.1.1.0 type=4 value=STRING: "TV channel HD (source) (udp://233.170.170.100:58631)"
SNMPv2-SMI::enterprises.50126.10.0.1.2.0 type=4 value=STRING: "VideoFreeze"
SNMPv2-SMI::enterprises.50126.10.0.1.10.0 type=4 value=STRING: "warning"
SNMPv2-SMI::enterprises.50126.10.0.1.3.0 type=4 value=Hex-STRING: 07 E5 06 11 0B 18 0D 00 2B 03 00
SNMPv2-SMI::enterprises.50126.10.0.1.4.0 type=4 value=Hex-STRING: 07 E5 06 11 0B 2E 1A 00 2B 03 00
SNMPv2-SMI::enterprises.50126.10.0.1.6.0 type=4 value=Hex-STRING: 07 E5 06 11 0B 2E 21 00 2B 03 00}

Current size of a log file is 25M.

This issue was present on previous 5.0.x versions too.