Steps to reproduce

1. Create a host named test-multiple-trigger monitored by a proxy or server.
2. Create the following items:
   • test.master.json (type: zabbix trapper)
   • test.name (dependent of master json)
   • test.surname (dependent of master json)
   • test.age (dependent of master json)
3. Create these triggers: 

Trigger A – Single item expression (works correctly)

last(/test-multiple-trigger/test.name)="Andrea"

Trigger B – Multi-item expression (problematic)

last(/test-multiple-trigger/test.name)="Mario" and
last(/test-multiple-trigger/test.surname)="Rossi" and
last(/test-multiple-trigger/test.age)>90

Trigger C – Multi-item expression (problematic)

last(/test-multiple-trigger/test.name)="Mario" and
last(/test-multiple-trigger/test.surname)="Rossi" and
last(/test-multiple-trigger/test.age)<=90

Configure both triggers with:

• Problem event generation mode: Multiple
• OK event generation: None

Send the following values five times:

The following two bash commands were executed on a Zabbix proxy to test both scenarios:
 

for i in {1..5}; do   zabbix_sender -v -z 127.0.0.1 -p 10051 -s test-multiple-trigger -k test.master.json -o '[{"name": "Mario","surname":"Rossi","age":100}]'; done


for i in {1..5}; do   zabbix_sender -v -z 127.0.0.1 -p 10051 -s test-multiple-trigger -k test.master.json -o '[{"name": "Andrea","surname":"Bianchi","age":30}]'; done 

After that:

Case 1 – Single item expression (expected behavior)

• Exactly 5 problem events are generated.
• Trigger fires once per value update.
• No duplicated or unexpected events.

Case 2 – Multi-item expression (incorrect behavior)

• More than 5 problem events are generated.
• Events are duplicated for the same value update.
• Trigger evaluation appears inconsistent when multiple items are evaluated together.
• This behavior occurs only when the trigger expression references more than one item.

Expected result

• Trigger behavior should be consistent regardless of the number of items used in the expression.
• With multiple items in an expression:
• Exactly one problem event per value update should be generated.
• No duplicated or overlapping events.

Key observation

• The issue does not occur when the trigger expression references only one item.
• The issue always occurs when the trigger expression references multiple items combined for example with AND conditions.
• This strongly suggests a problem in trigger evaluation and/or problem event generation logic for multi-item expressions.