When a user deleted a project that he created but all of our users (approx 250) received a notification in their emails of this transaction. We do not understand why this happened since the notification scheme is not configured this way or we do not know why this happened. The situation has been annoying because even the T.I. department analyzed whether it was not a security breach case. The deleted project that all those notifications were sent for is "A20-033 Allsups cremes with Film 5oz".
We contact attlassian support, but they have not solve anything yet.
Could you please check for us, why this notification were sent to all users? How to prevent this? These notifications were received by people who were not involved in the project.
Thank you.

This was the message received for all users.