Hello Spark Wang,
Thank you for reaching out to Microsoft Support!
After testing, as you mentioned, creationOptions will be returned for v1.0, but the key will not be returned for beta version.
According to the documentation, beta is the test version, the API under this version may change, obviously the endpoint has changed for the group API.
And beta version is not supported for use in production applications, so it is recommended that you use version v1.0.
Hope this helps.
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