I wasn’t able to repro this issue in this commit, also note there’s build issues with:
var client = new ServiceStack.JsonServiceClient("http://127.0.0.1:8088");
var CustomerQueryRequest = new CustomerQuery() { CustomerIDIn = new string[] { "1001", "1002" } };
var CustomerQueryResponse = client.Get(CustomerQueryRequest);
Please put together a stand-alone project we can run locally (e.g. on GitHub) to see this issue.