Hi @Rotem - this previous community post should help. Looks like there is a resolution for you here: https://community.atlassian.com/t5/Jira-questions/How-do-I-exclude-sub-task-creation-notification-emails-but-not/qaq-p/1278788
The notification scheme responds to events in the workflow, but also just editing an issue. You can get around the workflow by creating a new event names 'nonotification' or such and putting it in every post function in the workflow for subtasks. However, if you are notifying on creation or edits I don't know how you could do that.