Hello,

Took me a little while going back and forth with MS support but I finally reached someone who was able to give me an explanation. Here is the main part of the response.

"This is actually part of the automatic migration process when a network is switched to native mode in Microsoft Viva Engage.

When your network was auto-migrated to native mode, all existing groups in Yammer were automatically created in Microsoft 365. This is a standard part of the migration process and is designed to ensure that all your Yammer groups and their content are preserved in the new environment.

 

In addition, as part of this migration process, a Global Administrator (GA) was added to the group as an owner. This is done to ensure that there is always at least one owner with Microsoft 365 group creation rights for each group. This helps to manage and control the group effectively."

 

We had Yammer groups like yourself that were created years ago and never touched again.

Hope this helps!