Steps to reproduce:

1. Proxy and Agent on same machine
2. Configure snmp traps as per official documentation (use bash trap receiver)
3. Create host and template with snmp trap item (snmptrap.fallback)
4. Send test trap to proxy (for example "snmptrap -v 2c -c public 192.168.100.12 '' linkUp.0")

Result:

See trap in snmptraps.log file

See "unmatched trap received from xxx" in zabbix_proxy.log

See nothing under "latest data" in Zabbix GUI

Expected:

Should see trap content under "latest data" in Zabbix GUI