Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello VP Steve Wilsonn,
Good day. Thank you for posting in the community!
Sincere apologies for any inconvenience this issue might be causing you. It's a known issue by Microsoft. This issue has been escalated to the Microsoft Defender Team for a fix. We will update this topic as soon as the fix status is available. Below I am sharing the details:
ISSUE
Using the Microsoft Defender portal, you configure user reported settings and set “Monitor reported messages in Outlook” to be “Use a non-Microsoft add-in button”. After saving these changes and restarting classic Outlook you find the Report button is still available on the Outlook ribbon.

STATUS: INVESTIGATING
This issue has been escalated to the Microsoft Defender Team for a fix. We will update this topic as soon as the fix status is available.
This feature is associated with Microsoft 365 Roadmap ID 371388. Additional specifics about the rollout are published for tenant admins to access in the Admin Portal as message center post MC841229.
Roadmap Link: Microsoft 365 Roadmap | Microsoft 365
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Thank you very much for your valuable time and your cooperation.
Sincerely,
Md Ashabul Haque | Microsoft Community Moderator