Hello @Bedford, Jeana J ,
Welcome to the MS Q&A forum.
Yes, it seems you already found the answer. I am just confirming there. Once a privileged access group is managed, it can't be taken out of management. This prevents another resource administrator from removing Privileged Identity Management settings. The only way is to delete it.
Also, keep in mind if a privileged access group is deleted from Azure Active Directory, it may take up to 24 hours for the group to be removed from the Privileged access groups (Preview) blade.
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Sinserely,
Olga