Environment:

Zabbix: 7.4.x
iTop: 3.2.2
 
Issue:
Using the official iTop webhook from the integration page.
For newly generated trigger events:

event_value = 1
event_update_status = 0

the webhook receives:

itop_id = UNKNOWN

 Expected return:

itop_id = {EVENT.TAGS.__zbx_itop_id}

 Because of this condition:

&& Itop.params.id === '{EVENT.TAGS.__zbx_itop_id}'

 the code enters the update branch and sends:

operation=core/update
key=UNKNOWN

 instead of:

operation=core/create

 Result:

Request failed with iTop code 100:
Error: Query failed to execute: query = UNKNOWN

Possible Workaround:
Removing the condition:

&& Itop.params.id === '{EVENT.TAGS.__zbx_itop_id}'

 fixes the issue and ticket creation works correctly.