If an user subscribes to a Content object that already has some Content objects and there is some update on the Content object, and we run notification cronjob only after something has been changed. The notification will send notifications about all the Contents already created (before the subscription)

Steps

1. create an editor user A (with an email you have access)
2. create a Content object B with 1+ objects with Admin user
3. login on frontend with user A
4. subscribe to Content object B
5. IMPORTANT: do not run notification cronjob here
6. with Admin user create a new object inside B
7. run notification cronjob
8. verify that user A received an email for each object in B

If we do run the notification cronjob at IMPORTANT step this won't happen, as the user A will only receive the correct emails