The Dynamics 365 Get Record operation doesn't seem to have the capability to specify "odata.include-annotations" in the header. This is normally set to odata.include-annotations="*". For datatypes like EntityReference and OptionSet, not including this header means that the underlying text behind the Guid or Integer cannot be seen, as there is no formatted value on the response.
With odata.include-annotations header
{ @odata.context: "https://crmonline.crm6.dynamics.com/api/data/v8.2/$metadata#accounts(_modifiedby_value)", @Microsoft.Dynamics.CRM.totalrecordcount: -1, @Microsoft.Dynamics.CRM.totalrecordcountlimitexceeded: false, value: [0: { @odata.etag: "W/"4106932"", _modifiedby_value@OData.Community.Display.V1.FormattedValue: "Max Power", _modifiedby_value@Microsoft.Dynamics.CRM.lookuplogicalname: "systemuser", _modifiedby_value: "edf0b0bf-8949-4f09-9d5e-a41b8c31de00", accountid: "55ee1933-35ad-e711-a842-000d3ad0ed15" }] }
Without odata.include-annotations header
{ "@odata.context": "https://crmonline.crm6.dynamics.com/api/data/v8.2/$metadata#accounts(_modifiedby_value)", "value": [{ "@odata.etag": "W/\"4106932\"", "_modifiedby_value": "edf0b0bf-8949-4f09-9d5e-a41b8c31de00", "accountid": "55ee1933-35ad-e711-a842-000d3ad0ed15" }], }