Apparently, to add an owner by PUT /api/v2/groups/{groupId} you need the future owner to be a member of the group. You can do this by POST /api/v2/groups/{groupId}/members.
Remembering that POST /api/v2/groups makes the owner automatically the holder of the user's authorization.
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Gustavo Batista
PAGSEGURO INTERNET S/A
https://www.linkedin.com/in/gustavo-b-martins/
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