Hi Andrea Fuggetta,
Thanks for reaching out.
The systemConfiguration property does not appear to be one of the properties returned by the Teamwork/devices/id call and hence you cannot use select or expand it. For all the Teamwork devices properties please refer to article https://learn.microsoft.com/en-us/graph/api/resources/teamworkdevice?view=graph-rest-beta for more information.
For any Graph SDK related questions please post them on the respective Graph SDK Github forum. If you are able to produce the issue using Graph Explorer or Postman app please post any beta api issues on the Graph Feedback Forum.
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