Hi @Swapnil Dave ,
This is beacuse of Privacy changes to Microsoft 365 Usage Analytics: https://techcommunity.microsoft.com/t5/microsoft-365-blog/privacy-changes-to-microsoft-365-usage-analytics/ba-p/2694137
You could disable the feature by going to Settings > Org Settings > Services and selecting Reports, uncheck the option In all reports, display de-identified names for users, groups, and sites.
If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.