Environment version: 4.0.30319.42000
Json.NET version: Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed

Generated JSON: 
[
  {
    "Customer": {
      "Id": 1,
      "FirstName": "John",
      "Address": {
        "AddressLine1": "1 Street"
      }
    }
  },
  {
    "Customer": {
      "Id": 2,
      "FirstName": "Sam",
      "Address": {
        "AddressLine1": "Fedral Highway"
      }
    }
  }
]

Generated JSON is equivalent to required JSON.