Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear User,
Good day!! I hope you are doing well~
As per the description shared, I understand your concern and I would like to convey that I have tested the behavior at my end, where I am not able to reproduce the problem and the users who are assigned with the tasks in the Plan are also receiving the email notifications.
Since you have mentioned you and other users in your team are experiencing the same issue, where the same problem persists in the different locations, network, and computer; I have checked the service health dashboard at the Microsoft end, where there is no related incident found.
In this situation, I am sorry to convey that the problem you and your team are facing is not an expected behavior and it should be further investigated by the related development team, where they can collect the related logs via reproducing the problem and investigate the issue further.
So, I request you connect with the IT admin of your organization (How do I find my Microsoft 365 admin? - Microsoft Support) and ask them to raise a new service request from the Microsoft 365 admin center on your behalf to perform further investigation on this issue: Get support - Microsoft 365 admin | Microsoft Learn
Note: Please accept our sincere apologies for redirecting you to related development support team because the moderators in this community are limited with the resource for further investigation and to get a quick resolution to your problem, we requested it.
Appreciate your patience and understanding. Have a great day!!
Best Regards,
Sophia