I am a member of a team. That team has a project. When a task is created in that project, I get an email, even if I am not the creator of the task and it is not assigned to me. I am not a collaborator on the task. The entire history of one example task is as follows:
[Person 1] created this task. 1 hour ago
[Person 1] added to [Project name]. 1 hour ago
[Person 1] assigned to [Person 2]. 1 hour ago
[Peron 1] changed the due date to Tomorrow. 1 hour ago
The only collaborators in the task are Person 1 and Person 2.