I have run the below query in MS Graph to get user activity.
https://graph.microsoft.com/v1.0/reports/getOffice365ActiveUserDetail(period='D180')
I got deleted users in the result. And also, there is a flag called Is Deleted in the response, but it is false for all records. I have deleted users two days before from this question posted. I am getting always false in Is Deleted flag. I have searched Ms docs to find the purpose of this flag. Unluckily, I am not able to find it. Please help me to find out this.
Is deleted indicates that the user's license was removed but not that the user has been deleted from AAD.
Also: Activity for a deleted user will still display in the report as long as he or she was licensed at some time during the selected time period. The Deleted column helps you to note that the user may no longer be active, but contributed to the data in the report.
Try removing all Office licenses for a given user and get the report for the the following period.