diff --git a/src/NHibernate.Test/Async/NHSpecificTest/GH1235/OptionalJoinFixture.cs b/src/NHibernate.Test/Async/NHSpecificTest/GH1235/OptionalJoinFixture.cs
new file mode 100644
index 00000000000..5398f667d62
--- /dev/null
+++ b/src/NHibernate.Test/Async/NHSpecificTest/GH1235/OptionalJoinFixture.cs
@@ -0,0 +1,198 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using System.Linq;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Mapping.ByCode;
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+using NHibernate.Linq;
+
+namespace NHibernate.Test.NHSpecificTest.GH1235
+{
+	using System.Threading.Tasks;
+	//NH-2785
+	[TestFixture(OptimisticLockMode.None)]
+	[TestFixture(OptimisticLockMode.Version)]
+	[TestFixture(OptimisticLockMode.Dirty)]
+	public class OptionalJoinFixtureAsync : TestCaseMappingByCode
+	{
+		private readonly OptimisticLockMode _optimisticLock;
+
+		public OptionalJoinFixtureAsync(OptimisticLockMode optimisticLock)
+		{
+			_optimisticLock = optimisticLock;
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				if (Dialect.SupportsTemporaryTables)
+					session.CreateQuery("delete from System.Object").ExecuteUpdate();
+				else
+					session.Delete("from System.Object");
+
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public async Task UpdateNullOptionalJoinToNotNullAsync()
+		{
+			object id;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var entity = new MultiTableEntity { Name = "Bob" };
+				id = await (s.SaveAsync(entity));
+				await (t.CommitAsync());
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var e = await (s.GetAsync<MultiTableEntity>(id));
+				e.OtherName = "Sally";
+				await (t.CommitAsync());
+			}
+
+			using (var s = OpenSession())
+			{
+				var e = await (s.GetAsync<MultiTableEntity>(id));
+				Assert.That(e.OtherName, Is.EqualTo("Sally"));
+			}
+		}
+
+		[Test]
+		public async Task UpdateNullOptionalJoinToNotNullDetachedAsync()
+		{
+			object id;
+			MultiTableEntity entity;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				entity = new MultiTableEntity { Name = "Bob" };
+				id = await (s.SaveAsync(entity));
+				await (t.CommitAsync());
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				entity.OtherName = "Sally";
+				await (s.UpdateAsync(entity));
+				await (t.CommitAsync());
+			}
+
+			using (var s = OpenSession())
+			{
+				var e = await (s.GetAsync<MultiTableEntity>(id));
+				Assert.That(e.OtherName, Is.EqualTo("Sally"));
+			}
+		}
+
+		[Test]
+		public async Task ShouldThrowStaleStateForOptimisticLockUpdateAsync()
+		{
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var result = new MultiTableEntity { Name = "Bob", OtherName = "Bob" };
+				await (s.SaveAsync(result));
+				await (t.CommitAsync());
+			}
+
+			using (var s1 = OpenSession())
+			using (var t1 = s1.BeginTransaction())
+			{
+				var result = await (s1.Query<MultiTableEntity>().FirstOrDefaultAsync());
+
+				result.OtherName += "x";
+				using (var s2 = OpenSession())
+				{
+					var result2 = await (s2.Query<MultiTableEntity>().FirstOrDefaultAsync());
+					result2.OtherName += "y";
+					await (t1.CommitAsync());
+
+					using (var t2 = s2.BeginTransaction())
+						Assert.That(
+							() => t2.CommitAsync(),
+							_optimisticLock == OptimisticLockMode.None
+								? (IResolveConstraint) Throws.Nothing
+								: Throws.InstanceOf<StaleObjectStateException>());
+				}
+			}
+		}
+
+		[Test]
+		public async Task ShouldThrowStaleStateForOptimisticLockDeleteAsync()
+		{
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var result = new MultiTableEntity { Name = "Bob", OtherName = "Bob" };
+				await (s.SaveAsync(result));
+				await (t.CommitAsync());
+			}
+
+			using (var s1 = OpenSession())
+			using (var t1 = s1.BeginTransaction())
+			{
+				var result = await (s1.Query<MultiTableEntity>().FirstOrDefaultAsync());
+
+				result.OtherName += "x";
+				using (var s2 = OpenSession())
+				{
+					var result2 = await (s2.Query<MultiTableEntity>().FirstOrDefaultAsync());
+					await (s2.DeleteAsync(result2));
+					await (t1.CommitAsync());
+
+					using (var t2 = s2.BeginTransaction())
+						Assert.That(
+							() => t2.CommitAsync(),
+							_optimisticLock == OptimisticLockMode.None
+								? (IResolveConstraint) Throws.Nothing
+								: Throws.InstanceOf<StaleObjectStateException>());
+				}
+			}
+		}
+
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+			mapper.Class<MultiTableEntity>(
+				rc =>
+				{
+					rc.Id(x => x.Id, m => m.Generator(Generators.Native));
+					rc.DynamicUpdate(true);
+					rc.OptimisticLock(_optimisticLock);
+
+					if (_optimisticLock == OptimisticLockMode.Version)
+						rc.Version(x => x.Version, _ => { });
+
+					rc.Property(x => x.Name);
+					rc.Join(
+						"SecondTable",
+						m =>
+						{
+							m.Key(k => k.Column("Id"));
+							m.Property(x => x.OtherName);
+							m.Optional(true);
+						});
+				});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+	}
+}
diff --git a/src/NHibernate.Test/NHSpecificTest/GH1235/Entity.cs b/src/NHibernate.Test/NHSpecificTest/GH1235/Entity.cs
new file mode 100644
index 00000000000..feda2775d84
--- /dev/null
+++ b/src/NHibernate.Test/NHSpecificTest/GH1235/Entity.cs
@@ -0,0 +1,12 @@
+using System;
+
+namespace NHibernate.Test.NHSpecificTest.GH1235
+{
+	class MultiTableEntity
+	{
+		public virtual int Id { get; set; }
+		public virtual int Version { get; set; }
+		public virtual string Name { get; set; }
+		public virtual string OtherName { get; set; }
+	}
+}
diff --git a/src/NHibernate.Test/NHSpecificTest/GH1235/OptionalJoinFixture.cs b/src/NHibernate.Test/NHSpecificTest/GH1235/OptionalJoinFixture.cs
new file mode 100644
index 00000000000..578c6ece59d
--- /dev/null
+++ b/src/NHibernate.Test/NHSpecificTest/GH1235/OptionalJoinFixture.cs
@@ -0,0 +1,186 @@
+using System.Linq;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Mapping.ByCode;
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+namespace NHibernate.Test.NHSpecificTest.GH1235
+{
+	//NH-2785
+	[TestFixture(OptimisticLockMode.None)]
+	[TestFixture(OptimisticLockMode.Version)]
+	[TestFixture(OptimisticLockMode.Dirty)]
+	public class OptionalJoinFixture : TestCaseMappingByCode
+	{
+		private readonly OptimisticLockMode _optimisticLock;
+
+		public OptionalJoinFixture(OptimisticLockMode optimisticLock)
+		{
+			_optimisticLock = optimisticLock;
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				if (Dialect.SupportsTemporaryTables)
+					session.CreateQuery("delete from System.Object").ExecuteUpdate();
+				else
+					session.Delete("from System.Object");
+
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public void UpdateNullOptionalJoinToNotNull()
+		{
+			object id;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var entity = new MultiTableEntity { Name = "Bob" };
+				id = s.Save(entity);
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var e = s.Get<MultiTableEntity>(id);
+				e.OtherName = "Sally";
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			{
+				var e = s.Get<MultiTableEntity>(id);
+				Assert.That(e.OtherName, Is.EqualTo("Sally"));
+			}
+		}
+
+		[Test]
+		public void UpdateNullOptionalJoinToNotNullDetached()
+		{
+			object id;
+			MultiTableEntity entity;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				entity = new MultiTableEntity { Name = "Bob" };
+				id = s.Save(entity);
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				entity.OtherName = "Sally";
+				s.Update(entity);
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			{
+				var e = s.Get<MultiTableEntity>(id);
+				Assert.That(e.OtherName, Is.EqualTo("Sally"));
+			}
+		}
+
+		[Test]
+		public void ShouldThrowStaleStateForOptimisticLockUpdate()
+		{
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var result = new MultiTableEntity { Name = "Bob", OtherName = "Bob" };
+				s.Save(result);
+				t.Commit();
+			}
+
+			using (var s1 = OpenSession())
+			using (var t1 = s1.BeginTransaction())
+			{
+				var result = s1.Query<MultiTableEntity>().FirstOrDefault();
+
+				result.OtherName += "x";
+				using (var s2 = OpenSession())
+				{
+					var result2 = s2.Query<MultiTableEntity>().FirstOrDefault();
+					result2.OtherName += "y";
+					t1.Commit();
+
+					using (var t2 = s2.BeginTransaction())
+						Assert.That(
+							() => t2.Commit(),
+							_optimisticLock == OptimisticLockMode.None
+								? (IResolveConstraint) Throws.Nothing
+								: Throws.InstanceOf<StaleObjectStateException>());
+				}
+			}
+		}
+
+		[Test]
+		public void ShouldThrowStaleStateForOptimisticLockDelete()
+		{
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				var result = new MultiTableEntity { Name = "Bob", OtherName = "Bob" };
+				s.Save(result);
+				t.Commit();
+			}
+
+			using (var s1 = OpenSession())
+			using (var t1 = s1.BeginTransaction())
+			{
+				var result = s1.Query<MultiTableEntity>().FirstOrDefault();
+
+				result.OtherName += "x";
+				using (var s2 = OpenSession())
+				{
+					var result2 = s2.Query<MultiTableEntity>().FirstOrDefault();
+					s2.Delete(result2);
+					t1.Commit();
+
+					using (var t2 = s2.BeginTransaction())
+						Assert.That(
+							() => t2.Commit(),
+							_optimisticLock == OptimisticLockMode.None
+								? (IResolveConstraint) Throws.Nothing
+								: Throws.InstanceOf<StaleObjectStateException>());
+				}
+			}
+		}
+
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+			mapper.Class<MultiTableEntity>(
+				rc =>
+				{
+					rc.Id(x => x.Id, m => m.Generator(Generators.Native));
+					rc.DynamicUpdate(true);
+					rc.OptimisticLock(_optimisticLock);
+
+					if (_optimisticLock == OptimisticLockMode.Version)
+						rc.Version(x => x.Version, _ => { });
+
+					rc.Property(x => x.Name);
+					rc.Join(
+						"SecondTable",
+						m =>
+						{
+							m.Key(k => k.Column("Id"));
+							m.Property(x => x.OtherName);
+							m.Optional(true);
+						});
+				});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+	}
+}
diff --git a/src/NHibernate/Async/Persister/Entity/AbstractEntityPersister.cs b/src/NHibernate/Async/Persister/Entity/AbstractEntityPersister.cs
index d5005ea10af..1e9ec77f2ba 100644
--- a/src/NHibernate/Async/Persister/Entity/AbstractEntityPersister.cs
+++ b/src/NHibernate/Async/Persister/Entity/AbstractEntityPersister.cs
@@ -756,7 +756,7 @@ protected async Task<bool> UpdateAsync(object id, object[] fields, object[] oldF
 						if (CheckVersion(includeProperty))
 							await (VersionType.NullSafeSetAsync(statement, oldVersion, index, session, cancellationToken)).ConfigureAwait(false);
 					}
-					else if (entityMetamodel.OptimisticLockMode > Versioning.OptimisticLock.Version && oldFields != null)
+					else if (IsPropertyBasedOptimisticLocking(oldFields))
 					{
 						bool[] versionability = PropertyVersionability;
 						bool[] includeOldField = OptimisticLockMode == Versioning.OptimisticLock.All
@@ -785,7 +785,7 @@ protected async Task<bool> UpdateAsync(object id, object[] fields, object[] oldF
 					}
 					else
 					{
-						return Check(await (session.Batcher.ExecuteNonQueryAsync(statement, cancellationToken)).ConfigureAwait(false), id, j, expectation, statement);
+						return Check(await (session.Batcher.ExecuteNonQueryAsync(statement, cancellationToken)).ConfigureAwait(false), id, j, expectation, statement, IsPropertyBasedOptimisticLocking(oldFields));
 					}
 				}
 				catch (OperationCanceledException) { throw; }
@@ -891,7 +891,7 @@ public async Task DeleteAsync(object id, object version, int j, object obj, SqlC
 					{
 						await (VersionType.NullSafeSetAsync(statement, version, index, session, cancellationToken)).ConfigureAwait(false);
 					}
-					else if (entityMetamodel.OptimisticLockMode > Versioning.OptimisticLock.Version && loadedState != null)
+					else if (IsPropertyBasedOptimisticLocking(loadedState))
 					{
 						bool[] versionability = PropertyVersionability;
 						IType[] types = PropertyTypes;
@@ -915,7 +915,7 @@ public async Task DeleteAsync(object id, object version, int j, object obj, SqlC
 					}
 					else
 					{
-						Check(await (session.Batcher.ExecuteNonQueryAsync(statement, cancellationToken)).ConfigureAwait(false), tableId, j, expectation, statement);
+						Check(await (session.Batcher.ExecuteNonQueryAsync(statement, cancellationToken)).ConfigureAwait(false), tableId, j, expectation, statement, IsPropertyBasedOptimisticLocking(loadedState));
 					}
 				}
 				catch (OperationCanceledException) { throw; }
diff --git a/src/NHibernate/Persister/Entity/AbstractEntityPersister.cs b/src/NHibernate/Persister/Entity/AbstractEntityPersister.cs
index ccad078e322..fd0dd32ceb0 100644
--- a/src/NHibernate/Persister/Entity/AbstractEntityPersister.cs
+++ b/src/NHibernate/Persister/Entity/AbstractEntityPersister.cs
@@ -2516,7 +2516,13 @@ protected IUniqueEntityLoader CreateEntityLoader(LockMode lockMode)
 			return CreateEntityLoader(lockMode, CollectionHelper.EmptyDictionary<string, IFilter>());
 		}
 
+		//TODO 6.0: Remove (replaced by overload with optional parameter) 
 		protected bool Check(int rows, object id, int tableNumber, IExpectation expectation, DbCommand statement)
+		{
+			return Check(rows, id, tableNumber, expectation, statement, false);
+		}
+
+		protected bool Check(int rows, object id, int tableNumber, IExpectation expectation, DbCommand statement, bool forceThrowStaleException = false)
 		{
 			try
 			{
@@ -2524,13 +2530,15 @@ protected bool Check(int rows, object id, int tableNumber, IExpectation expectat
 			}
 			catch (StaleStateException sse)
 			{
-				if (!IsNullableTable(tableNumber))
+				if (forceThrowStaleException || !IsNullableTable(tableNumber))
 				{
 					if (Factory.Statistics.IsStatisticsEnabled)
 						Factory.StatisticsImplementor.OptimisticFailure(EntityName);
 
 					throw new StaleObjectStateException(EntityName, id, sse);
 				}
+
+				return false;
 			}
 			catch (TooManyRowsAffectedException ex)
 			{
@@ -2592,7 +2600,7 @@ protected internal SqlCommandInfo GenerateUpdateString(bool[] includeProperty, i
 					hasColumns = true;
 				}
 			}
-			else if (entityMetamodel.OptimisticLockMode > Versioning.OptimisticLock.Version && oldFields != null)
+			else if (IsPropertyBasedOptimisticLocking(oldFields))
 			{
 				// we are using "all" or "dirty" property-based optimistic locking
 				bool[] includeInWhere =
@@ -2636,6 +2644,11 @@ protected internal SqlCommandInfo GenerateUpdateString(bool[] includeProperty, i
 			return hasColumns ? updateBuilder.ToSqlCommandInfo() : null;
 		}
 
+		private bool IsPropertyBasedOptimisticLocking(object[] oldFields)
+		{
+			return entityMetamodel.OptimisticLockMode > Versioning.OptimisticLock.Version && oldFields != null;
+		}
+
 		private bool CheckVersion(bool[] includeProperty)
 		{
 			return includeProperty[VersionProperty] || entityMetamodel.PropertyUpdateGenerationInclusions[VersionProperty] != ValueInclusion.None;
@@ -3219,7 +3232,7 @@ protected bool Update(object id, object[] fields, object[] oldFields, object row
 						if (CheckVersion(includeProperty))
 							VersionType.NullSafeSet(statement, oldVersion, index, session);
 					}
-					else if (entityMetamodel.OptimisticLockMode > Versioning.OptimisticLock.Version && oldFields != null)
+					else if (IsPropertyBasedOptimisticLocking(oldFields))
 					{
 						bool[] versionability = PropertyVersionability;
 						bool[] includeOldField = OptimisticLockMode == Versioning.OptimisticLock.All
@@ -3248,7 +3261,7 @@ protected bool Update(object id, object[] fields, object[] oldFields, object row
 					}
 					else
 					{
-						return Check(session.Batcher.ExecuteNonQuery(statement), id, j, expectation, statement);
+						return Check(session.Batcher.ExecuteNonQuery(statement), id, j, expectation, statement, IsPropertyBasedOptimisticLocking(oldFields));
 					}
 				}
 				catch (StaleStateException e)
@@ -3352,7 +3365,7 @@ public void Delete(object id, object version, int j, object obj, SqlCommandInfo
 					{
 						VersionType.NullSafeSet(statement, version, index, session);
 					}
-					else if (entityMetamodel.OptimisticLockMode > Versioning.OptimisticLock.Version && loadedState != null)
+					else if (IsPropertyBasedOptimisticLocking(loadedState))
 					{
 						bool[] versionability = PropertyVersionability;
 						IType[] types = PropertyTypes;
@@ -3376,7 +3389,7 @@ public void Delete(object id, object version, int j, object obj, SqlCommandInfo
 					}
 					else
 					{
-						Check(session.Batcher.ExecuteNonQuery(statement), tableId, j, expectation, statement);
+						Check(session.Batcher.ExecuteNonQuery(statement), tableId, j, expectation, statement, IsPropertyBasedOptimisticLocking(loadedState));
 					}
 				}
 				catch (Exception e)