I guess there is a lack of information. Is it possible to add a hardware token to several tenants? It seems that there will be no error, but it looks like while processing a new uploaded file, the processing will not come to an end.
Furthermore I'm wondering how additional new tokens should be added. Should I upload my CSV "master" file again with the new tokens added, or is it ok to upload a new file only with the new tokens? Nevertheless, I have not been able to upload further files. The notifications about the current processing status are not helpful, in most cases they show 0 failures, 0 success.
Can anyone shed some light into this case?
BTW: Some additional information I figuered out. If you started the MFA registration via TAP (temporary access pass) via aka.ms/mysecuritysignins you are allowed to add a FIDO2 token directly without have a backup telephone numer added. But you are always enforced to have a backup phone number whilst having an OATH hardware token assigned, even if you are eligible to start the registration via TAP.