I am working on creating an automated sub-task dependant on entry of a custom field. I have got this working and I am looking to send a notification to the assignee (Custom field from parent) on sub task creation. I have tried a few things, I have created a new notification scheme specifically for this and tried it using Issue Created and Issue Assigned independently. Around 50% of tests are sending notifications to users but some users are not receiving anything. Is there a setting higher than this that the user could potentially select that is stopping these being sent? I have looked at user settings to ensure they have receive notification on, but still issues.