You may have noticed some data missing or in the wrong format in Advanced Report. Microsoft implemented and activated a new feature for all tenants to mask user data in reports as of September 1st, 2021. Unfortunately, this also affects resources that Office Protect uses to produce reports.

To ensure that Advanced Report can correctly fetch data, you need to go to your tenant's Admin Center, in the Settings/Org Settings, find Reports in the Services tab. Ensure that "Display concealed users, group, and site names in all reports" is unchecked, and save your setting.

Microsoft's documentation on activity reports data privacy: