devices expand=registeredUsers does only return the id

Describe the bug

Using the devices endpoint in graph and the parameter expand=registeredUsers is supposed to return (all) values for all registered users.
Each registered user is supposed to be of type #microsoft.graph.user
Using graph-explorer, this works, i.e. https://graph.microsoft.com/beta//devices?$expand=registeredUsers
will contain a list of microsoft.graph.user objects in the registeredUsers property, where each user has attributes like mail, imAddresses etc filled.
Using the SDK only the id property for the microsoft.graph.user object is filled, i.e. all other properties are None or empty collections.

Is this a bug or something on my end I don't understand?

my calling code (broken down):

request_config = DevicesRequestBuilder.DevicesRequestBuilderGetQueryParameters(
        top=20,
        expand=['registeredUsers']
    )
self._event_loop.run_until_complete(self._graph_service.devices.get(request_config))

where _event_loop == asyncio.get_event_loop()
and _graph_service == GraphServiceClient

Expected behavior

A list of devices is returned, where registered Users of type #microsoft.graph.user in the device's registeredUsers property have more properties filled than just the ID

How to reproduce

See description

SDK Version

1.56.0

Latest version known to work for scenario above?

No response

Known Workarounds

No response

Debug output

No response

Configuration

• OS: MacOS 26.3.1
• Arch: Apple Silicon
• Python: 3.13.7 (venv)

Other information

No response

まず、expand=['registeredUsers'] を指定して GraphServiceClient と DevicesRequestBuilder 経由でリクエストを再現し、その後 SDK のレスポンスと Graph Explorer のレスポンスを比較します。返されたデバイスオブジェクトで registeredUsers がどのように表現され、設定されているかを追跡します。完了条件は、展開されたユーザーが id 以外のプロパティを公開し、サービスのレスポンスと一致することです。