Steps to reproduce:

We have a server that sends us SNMP trap to our Zabbix server. Name of the host that actually have a problem is contained in the trap; this is stored in a item. Triggers configuration are as follows:

Problem: last(/whatever/snmptrap.alarm.code)=123 and last(/whatever/snmptrap.alarm.resolution)=1
Recovery: last(/whatever/snmptrap.alarm.code)=123 and last(/whatever/snmptrap.alarm.resolution)=2

Tested on Zabbix 6.0 and 6.0.21, both on Ubuntu 20.04.6 LTS

Result:

Sometimes, when zabbix receive different traps, it triggers fake problems. The moment of the fake problem usually is the same as the resolution of another problem. During this event, there is no snmp trap that match the trigger expression. In attachment an example of this fake problem and the snmp log. 

Expected:

It should not trigger a problem that does not match the expression.