Nullable Index Fields Issue

using System;
using System.Linq;
using Raven.Abstractions.Indexing;
using Raven.Client;
using Raven.Client.Indexes;
using Xunit;

namespace Raven.Tests.MailingList
{
    public class NullableIssue : RavenTest
	{
		public class Person
		{
			public string Name { get; set; }
			public string NickName { get; set; }
			public DateTime? Birthday { get; set; }
		}

		public class PersonQuery
		{
			public string Query { get; set; }
		}

		public class PersonBrief
		{
			public string NickName { get; set; }
			public DateTime? Birthday { get; set; }
		}

		public class Person_PersonBrief : AbstractIndexCreationTask<Person>
		{
			public Person_PersonBrief()
			{
				Map = docs => from doc in docs
				              select new {Query = new object[] {doc.Name, doc.NickName}};

				TransformResults = (db, docs) =>
				                   from doc in docs
				                   select new {NickName = doc.NickName, Birthday = doc.Birthday};

				Index("Query", FieldIndexing.Analyzed);
			}
		}

		[Fact]
		public void Main()
		{
			using (var store = NewDocumentStore())
			{
				store.ExecuteIndex(new Person_PersonBrief());

				using (var session = store.OpenSession())
				{
					session.Store(new Person {Name = "Phil", NickName = "p1", Birthday = DateTime.Now.AddYears(-33)});
					session.Store(new Person {Name = "John", NickName = "j1", Birthday = DateTime.Now.AddYears(-22)});
					session.Store(new Person {Name = "Jamie", NickName = "j2"});
					session.SaveChanges();
				}

				using (var session = store.OpenSession())
				{
					var results = session.Query<PersonQuery, Person_PersonBrief>()
						.Customize(x=>x.WaitForNonStaleResults())
						.Where(x => x.Query.StartsWith("J"))
						.AsProjection<PersonBrief>()
						.ToList();

					Assert.NotEmpty(results);
				}
			}
		}
	}
}