Trying to reproduce a raven db error

RavenDBError

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NUnit.Framework;
using Raven.Abstractions.Data;
using Raven.Client.Document;
using Raven.Client.Indexes;

namespace RavenDBError
{
    [TestFixture]
    public class RavenPolymorphismTests
    {
        [Test]
        public void TestA()
        {
            IEnumerable<MyInterface> objects = new List<MyInterface>
                                                   {
                                                       new ImplA() {CommonInt = 0, IntA = 0, StringA = "0"},
                                                       new ImplB() {CommonInt = 2, IntB = 2, StringB = "2"},
                                                       new ImplA() {CommonInt = 1, IntA = 1, StringA = "1"},
                                                       new ImplB() {CommonInt = 3, IntB = 3, StringB = "3"}
                                                   };
            var ravenStore = new RavenStore();
            ravenStore.DeleteCollection();
            ravenStore.InsertBatch(objects);
            var objectsFromRaven = ravenStore.GetAll();
            for (int i = 0; i < objects.Count(); i++)
            {
                Assert.AreEqual(objects.ElementAt(i), objectsFromRaven.ElementAt(i));
            }
        }

    }

    public class MyObjects_ById : AbstractIndexCreationTask<MyInterface>
    {
        public MyObjects_ById()
        {
            Map = myObjects => from myObject in myObjects select new { Id = myObject.Id };
        }

        public static string IndexName { get { return "MyObjects/ById"; } }
    }

    public class RavenStore
    {
        private DocumentStore _documentStore;

        public RavenStore()
        {
            _documentStore = new DocumentStore
                                 {
                                     Url = "http://localhost:8090/",
                                     Conventions =
                                         {
                                             FindTypeTagName = type =>
                                                                   {
                                                                       if (typeof(MyInterface).IsAssignableFrom(type))
                                                                       {
                                                                           return "MyObjects";
                                                                       }
                                                                       return DocumentConvention.DefaultTypeTagName(type);
                                                                   }
                                         }
                                 };
            _documentStore.Initialize();
            IndexCreation.CreateIndexes(typeof(MyObjects_ById).Assembly, _documentStore);
        }

        public void InsertBatch(IEnumerable<MyInterface> eventBatch)
        {
            using (var session = _documentStore.OpenSession())
            {
                foreach (var domainEvent in eventBatch)
                {
                    session.Store(domainEvent);
                }
                session.SaveChanges();
            }
        }

        public IEnumerable<MyInterface> GetAll()
        {
            using (var session = _documentStore.OpenSession())
            {
                var obects = session.Query<MyInterface>(MyObjects_ById.IndexName);
                return obects;
            }
        }

        internal void DeleteCollection()
        {
            using (var session = _documentStore.OpenSession())
            {
                _documentStore.DatabaseCommands.DeleteByIndex(MyObjects_ById.IndexName, new IndexQuery());
                session.SaveChanges();
            }
        }
    }

    public interface MyInterface
    {
        Guid Id { get; set; }
        int CommonInt { get; set; }
    }

    abstract class BaseClass : MyInterface
    {
        public Guid Id { get; set; }

        public int CommonInt { get; set; }
        // override object.Equals
        public override bool Equals(object obj)
        {
            var otherObj = obj as BaseClass;
            if (obj == null)
            {
                return false;
            }
            return otherObj.CommonInt == CommonInt && otherObj.Id == Id;
        }

        public override int GetHashCode()
        {
            return base.GetHashCode();
        }
    }

    class ImplA : BaseClass
    {
        public int IntA { get; set; }
        public string StringA { get; set; }
        public override bool Equals(object obj)
        {
            var otherObj = obj as ImplA;
            if(otherObj == null)
            {
                return false;
            }
            if (IntA == otherObj.IntA && StringA == otherObj.StringA)
            {
                return base.Equals(obj);
            }
            return false;
        }
    }

    class ImplB : BaseClass
    {
        public int IntB { get; set; }
        public string StringB { get; set; }
        public override bool Equals(object obj)
        {
            var otherObj = obj as ImplB;
            if (otherObj == null)
            {
                return false;
            }
            if (IntB == otherObj.IntB && StringB == otherObj.StringB)
            {
                return base.Equals(obj);
            }
            return false;
        }
    }
}