Rows are missing from CassandraDB?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using FluentCassandra;

namespace ConsoleApplication2
{
	class Program
	{
		static void Main(string[] args)
		{
			var session = new CassandraSession("Tester", "localhost");

			CreateData(session);
			SelectData(session);
			Console.WriteLine("Done");
			Console.ReadLine();
		}

		private static void SelectData(CassandraSession session)
		{
			using (var db = new CassandraContext(session))
			{
				var users = db.GetColumnFamily("Users2");
				var count = users.AsObjectQueryable<User>().Count();
				Console.WriteLine("Counted: " + count.ToString());
			}
		}

		private static void CreateData(CassandraSession session)
		{
			var startTime = DateTime.UtcNow;
			for (int index = 0; index < 11 * 1000; index++)
			{
				using (var db = new CassandraContext(session))
				{
					var users = db.GetColumnFamily("Users2");
					dynamic user = users.CreateRecord(index);
					user.Name = "UserX" + index.ToString();
					user.Password = "PasswordX" + index.ToString();
					db.Attach(user);
					db.SaveChanges();
					if (index % 1000 == 0)
					{
						var taken = DateTime.UtcNow - startTime;
						Console.WriteLine(string.Format("{0} thousand in {1} seconds", (index / 1000) + 1, taken.TotalSeconds));
					}
				}
			}
		}
	}

	class User
	{
		public string Name { get; set; }
		public string Text { get; set; }
	}
}

Output:
1 thousand in 0.2760158 seconds
2 thousand in 0.8180468 seconds
3 thousand in 1.3700784 seconds
4 thousand in 1.8971085 seconds
5 thousand in 2.4091378 seconds
6 thousand in 3.0791761 seconds
7 thousand in 3.6002059 seconds
8 thousand in 4.126236 seconds
9 thousand in 4.8292762 seconds
10 thousand in 5.3513061 seconds
11 thousand in 5.8543349 seconds
Counted: 9018
Done