Expiry returned with entire document when ContentAs invoked

var jObject = new JObject

{

    ["TestProp"] = "SomeValue"

};

var mutResult1 = await collection.InsertAsync(id1, jObject, insertOptions => insertOptions

    .Expiry(TimeSpan.FromMilliseconds(10000)));

var getResult1 = await collection.GetAsync(id1);

var value1 = getResult1.ContentAs<JObject>();

Console.WriteLine(value1.ToString(Formatting.Indented));

Console.WriteLine("--------------------------------------------");

var getResult2 = await collection.GetAsync(id1, getOptions => getOptions.Expiry());

var value2 = getResult2.ContentAs<JObject>();

Console.WriteLine(value2.ToString(Formatting.Indented));

{

  "TestProp": "SomeValue"

}

{

  "$document": {

    "exptime": 1598520403

  },

  "": {

    "TestProp": "SomeValue"

  }

}