Steps to reproduce:

1. Go to Data collection -> Hosts -> Zabbix server -> Triggers
2. Open any templated trigger with unchecked "Allow manual close"
3. Click on the Parent trigger link in the trigger's form

Result:
Alert "Changes will be lost" is appearing

See video(both "Allow manual close" checked and unchecked scenarios for same trigger):

Expected:
No alert should be present in such scenario