Change Tracking - Single property update of entity seems broken about entityframework-effort HOT 5 CLOSED

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Data.Entity;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Effort.Lab.EF6
{
	public partial class Form_Request_trackingProperty : Form
	{
		public Form_Request_trackingProperty()
		{
			InitializeComponent();
            var connection = Effort.DbConnectionFactory.CreateTransient();

            // CLEAN
            using (var context = new EntityContext(connection))
            {
                context.EntitySimples.RemoveRange(context.EntitySimples);
                context.SaveChanges();
            }

            // SEED
            using (var context = new EntityContext(connection))
            {
                context.EntitySimples.Add(new EntitySimple { ColumnInt = 1 });
                context.EntitySimples.Add(new EntitySimple { ColumnInt = 2 });
                context.EntitySimples.Add(new EntitySimple { ColumnInt = 3 });
                context.SaveChanges();
            }

            EntitySimple entity = new EntitySimple();
			
            using (var context2 = new EntityContext(connection))
			{

                using (var context = new EntityContext(connection))
                {
                    entity = context.EntitySimples.AsNoTracking().First();
                }

                entity.ColumnInt = 50;

                // TEST
                using (var context = new EntityContext(connection))
                { 
                    context.EntitySimples.Attach(entity);
                    context.Entry(entity).Property(nameof(EntitySimple.ColumnInt)).IsModified = true;
                    context.SaveChanges(); 
                }  

                var check2 = context2.EntitySimples.AsNoTracking().ToList();

				// TEST
                using (var context = new EntityContext(connection))
                {
                    var check = context.EntitySimples.AsNoTracking().ToList();
                }
            }
        }

        public class EntityContext : DbContext
        {
            public EntityContext(DbConnection connection) : base(connection, true)
            {
            }

            public DbSet<EntitySimple> EntitySimples { get; set; }


            protected override void OnModelCreating(DbModelBuilder modelBuilder)
            {
                base.OnModelCreating(modelBuilder);
            }
        }

        public class EntitySimple
        {
            public int ID { get; set; }
            public int ColumnInt { get; set; }
        }
    }
}