Steps to reproduce:

1. Use any default SNMP template
2. Set {$SNMP.TIMEOUT} macro to 10m
3. Wait 10m
4. SNMP service goes down

Result:
"No SNMP data collection" trigger ignores {$SNMP.TIMEOUT} and fires immediately

Expected:
"No SNMP data collection" trigger fires after {$SNMP.TIMEOUT}

This issue affects all templates that have Discard unchanged with hearbeat on SNMP agent availability item. I count 36 SNMP templates in 5 template folders like this:

• net/cisco/cisco_asav_snmp/
• net/zyxel_snmp/
• power/apc/
• server/cisco_ucs_manager_snmp/
• server/dell/ server/hp/

Generally, doing good triggers with Discard unchanged with heartbeat items is surprisingly hard.