A cloud-based identity and access management service for securing user authentication and resource access
Hello H Raja,
Whenever a user, service principal, or group that has an Azure RBAC role assignment at the management group, subscription, or resource level is deleted in Microsoft Entra ID without first removing the RBAC assignment, you may notice that the security principal is shown as Identity not found with an Unknown type. Please refer to the screenshot from my test tenant below.
To confirm whether these assignments are safe to remove: whenever you see an RBAC assignment with an Unknown type, it means the object no longer exists in the tenant and it is safe to delete the role assignment without any issues.
For more information, please refer to the public documentation below:
Role assignments with Identity not found with an Unknown type
Note: As these objects were already deleted from your directory there is no way that we can find out that information.
I hope this information is helpful. Please feel free to reach out if you have any further questions.