diff --git a/src/NHibernate.Test/Async/StaticProxyTest/InterfaceHandling/Fixture.cs b/src/NHibernate.Test/Async/StaticProxyTest/InterfaceHandling/Fixture.cs
new file mode 100644
index 00000000000..80cb249dce3
--- /dev/null
+++ b/src/NHibernate.Test/Async/StaticProxyTest/InterfaceHandling/Fixture.cs
@@ -0,0 +1,202 @@
+//------------------------------------------------------------------------------
+// <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;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Mapping.ByCode;
+using NUnit.Framework;
+
+namespace NHibernate.Test.StaticProxyTest.InterfaceHandling
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class FixtureAsync : TestCaseMappingByCode
+	{
+		private readonly Guid _id = Guid.NewGuid();
+
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+
+			#region Subclass hierarchy
+
+			mapper.Class<EntityClassProxy>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.UnionSubclass<SubEntityInterfaceProxy>(
+				rc =>
+				{
+					rc.Proxy(typeof(ISubEntityProxy));
+
+					rc.Property(x => x.AnotherName);
+				});
+
+			mapper.UnionSubclass<AnotherSubEntityInterfaceProxy>(
+				rc =>
+				{
+					rc.Proxy(typeof(IAnotherEntityProxy));
+
+					rc.Property(x => x.AnotherName);
+				});
+
+			mapper.Class<EntityWithSuperClassInterfaceLookup>(
+				rc =>
+				{
+					rc.Table("ClassWithInterfaceLookup");
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+					rc.ManyToOne(x => x.EntityLookup, x => x.Class(typeof(EntityClassProxy)));
+				});
+
+			#endregion Subclass hierarchy
+
+			mapper.Class<EntitySimple>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityExplicitInterface>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityMultiInterfaces>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityMixExplicitImplicitInterface>(
+				rc =>
+				{
+					rc.Table("multiInterface");
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityMultiIdProxy>(
+				rc =>
+				{
+					rc.Proxy(typeof(IMultiIdProxy));
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+
+		[Test]
+		public async Task ProxyForBaseSubclassCanBeCreatedAsync()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = await (session.LoadAsync<EntityClassProxy>(_id));
+			}
+		}
+
+		//Id access via implicit interface should not lead to proxy initialization
+		[Test]
+		public async Task ProxyClassIdAccessByImplicitInterfaceAsync()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = (IEntity) await (session.LoadAsync<EntitySimple>(_id));
+				CanAccessIEntityId(entity);
+				ThrowOnIEntityNameAccess(entity);
+				Assert.That(entity.Id, Is.EqualTo(_id));
+
+				var multiInterface = await (session.LoadAsync<EntityMultiInterfaces>(_id));
+				CanAccessIEntityId(multiInterface);
+				CanAccessIEntity2Id(multiInterface);
+				Assert.That(multiInterface.Id, Is.EqualTo(_id));
+			}
+		}
+
+		[Test]
+		public async Task ProxyClassIdAccessExplicitInterfaceAsync()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = await (session.LoadAsync<EntityExplicitInterface>(_id));
+
+				ThrowOnIEntityIdAccess(entity);
+				Assert.That(entity.Id, Is.EqualTo(_id));
+			}
+		}
+
+		[Test]
+		public async Task ProxyClassIdAccessBothImplicitExplicitInterfacesAsync()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = await (session.LoadAsync<EntityMixExplicitImplicitInterface>(_id));
+
+				//IEntity2 is implicit and should be accessible without proxy initialization
+				CanAccessIEntity2Id(entity);
+				ThrowOnIEntityIdAccess(entity);
+			}
+		}
+
+		[Test]
+		public async Task ProxyInterfaceIdAccessAsync()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = await (session.LoadAsync<ISubEntityProxy>(_id));
+
+				CanAccessIEntityId(entity);
+			}
+		}
+
+		[KnownBug("GH-2271")]
+		[Test]
+		public async Task ProxyInterfaceIdAccessFromDifferentInterfacesAsync()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = await (session.LoadAsync<IMultiIdProxy>(_id));
+
+				CanAccessIEntityId(entity);
+				CanAccessIEntity2Id(entity);
+			}
+		}
+
+		private void ThrowOnIEntityNameAccess(IEntity entity)
+		{
+			Assert.That(() => entity.Name, Throws.TypeOf<ObjectNotFoundException>(), "IEntity.Name access should lead to proxy initialization");
+		}
+
+		private void ThrowOnIEntityIdAccess(IEntity entity)
+		{
+			Assert.That(() => entity.Id, Throws.TypeOf<ObjectNotFoundException>(), "IEntity.Id access should lead to proxy initialization");
+		}
+
+		private void CanAccessIEntityId(IEntity entity)
+		{
+			Assert.That(() => entity.Id, Throws.Nothing, "Failed to access proxy IEntity.Id interface");
+			Assert.That(entity.Id, Is.EqualTo(_id));
+		}
+
+		private void CanAccessIEntity2Id(IEntity2 entity)
+		{
+			Assert.That(() => entity.Id, Throws.Nothing, "Failed to access proxy IEntity2.Id interface");
+			Assert.That(entity.Id, Is.EqualTo(_id));
+		}
+	}
+}
diff --git a/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/BaseInterfaces.cs b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/BaseInterfaces.cs
new file mode 100644
index 00000000000..7beade98061
--- /dev/null
+++ b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/BaseInterfaces.cs
@@ -0,0 +1,16 @@
+using System;
+
+namespace NHibernate.Test.StaticProxyTest.InterfaceHandling
+{
+	public interface IEntity
+	{
+		Guid Id { get; set; }
+
+		string Name { get; set; }
+	}
+
+	public interface IEntity2
+	{
+		Guid Id { get; set; }
+	}
+}
diff --git a/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Entities.cs b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Entities.cs
new file mode 100644
index 00000000000..37976a51382
--- /dev/null
+++ b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Entities.cs
@@ -0,0 +1,82 @@
+using System;
+
+namespace NHibernate.Test.StaticProxyTest.InterfaceHandling
+{
+	public class EntitySimple : IEntity
+	{
+		public virtual Guid Id { get; set; }
+
+		public virtual string Name { get; set; }
+	}
+
+	public class EntityMultiInterfaces : IEntity, IEntity2
+	{
+		public virtual Guid Id { get; set; }
+
+		public virtual string Name { get; set; }
+	}
+
+	public class EntityExplicitInterface : IEntity
+	{
+		private Guid id;
+		private string name;
+
+		public virtual Guid Id { get; set; }
+
+		public virtual string Name { get; set; }
+
+		Guid IEntity.Id
+		{
+			get => id;
+			set => id = value;
+		}
+
+		string IEntity.Name
+		{
+			get => name;
+			set => name = value;
+		}
+	}
+
+	//Proxy contains IEntity.Id and IEntity2.Id
+	public interface IMultiIdProxy : IEntity, IEntity2
+	{
+	}
+
+	public class EntityMultiIdProxy : IMultiIdProxy
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+	}
+
+	public class EntityMixExplicitImplicitInterface : IEntity, IEntity2
+	{
+		private Guid id;
+		private string name;
+
+		public virtual Guid Id { get; set; }
+
+		public virtual string Name { get; set; }
+
+		Guid IEntity.Id
+		{
+			get => id;
+			set => id = value;
+		}
+
+		string IEntity.Name
+		{
+			get => name;
+			set => name = value;
+		}
+	}
+
+	public class EntityWithSuperClassInterfaceLookup
+	{
+		public virtual Guid Id { get; set; }
+
+		public virtual string Name { get; set; }
+
+		public virtual IEntity EntityLookup { get; set; }
+	}
+}
diff --git a/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Fixture.cs b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Fixture.cs
new file mode 100644
index 00000000000..b2e9e36becb
--- /dev/null
+++ b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Fixture.cs
@@ -0,0 +1,196 @@
+using System;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Mapping.ByCode;
+using NUnit.Framework;
+
+namespace NHibernate.Test.StaticProxyTest.InterfaceHandling
+{
+	[TestFixture]
+	public class Fixture : TestCaseMappingByCode
+	{
+		private readonly Guid _id = Guid.NewGuid();
+
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+
+			#region Subclass hierarchy
+
+			mapper.Class<EntityClassProxy>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.UnionSubclass<SubEntityInterfaceProxy>(
+				rc =>
+				{
+					rc.Proxy(typeof(ISubEntityProxy));
+
+					rc.Property(x => x.AnotherName);
+				});
+
+			mapper.UnionSubclass<AnotherSubEntityInterfaceProxy>(
+				rc =>
+				{
+					rc.Proxy(typeof(IAnotherEntityProxy));
+
+					rc.Property(x => x.AnotherName);
+				});
+
+			mapper.Class<EntityWithSuperClassInterfaceLookup>(
+				rc =>
+				{
+					rc.Table("ClassWithInterfaceLookup");
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+					rc.ManyToOne(x => x.EntityLookup, x => x.Class(typeof(EntityClassProxy)));
+				});
+
+			#endregion Subclass hierarchy
+
+			mapper.Class<EntitySimple>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityExplicitInterface>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityMultiInterfaces>(
+				rc =>
+				{
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityMixExplicitImplicitInterface>(
+				rc =>
+				{
+					rc.Table("multiInterface");
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			mapper.Class<EntityMultiIdProxy>(
+				rc =>
+				{
+					rc.Proxy(typeof(IMultiIdProxy));
+					rc.Id(x => x.Id);
+					rc.Property(x => x.Name);
+				});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+
+		[Test]
+		public void ProxyForBaseSubclassCanBeCreated()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = session.Load<EntityClassProxy>(_id);
+			}
+		}
+
+		//Id access via implicit interface should not lead to proxy initialization
+		[Test]
+		public void ProxyClassIdAccessByImplicitInterface()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = (IEntity) session.Load<EntitySimple>(_id);
+				CanAccessIEntityId(entity);
+				ThrowOnIEntityNameAccess(entity);
+				Assert.That(entity.Id, Is.EqualTo(_id));
+
+				var multiInterface = session.Load<EntityMultiInterfaces>(_id);
+				CanAccessIEntityId(multiInterface);
+				CanAccessIEntity2Id(multiInterface);
+				Assert.That(multiInterface.Id, Is.EqualTo(_id));
+			}
+		}
+
+		[Test]
+		public void ProxyClassIdAccessExplicitInterface()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = session.Load<EntityExplicitInterface>(_id);
+
+				ThrowOnIEntityIdAccess(entity);
+				Assert.That(entity.Id, Is.EqualTo(_id));
+			}
+		}
+
+		[Test]
+		public void ProxyClassIdAccessBothImplicitExplicitInterfaces()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = session.Load<EntityMixExplicitImplicitInterface>(_id);
+
+				//IEntity2 is implicit and should be accessible without proxy initialization
+				CanAccessIEntity2Id(entity);
+				ThrowOnIEntityIdAccess(entity);
+			}
+		}
+
+		[Test]
+		public void ProxyInterfaceIdAccess()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = session.Load<ISubEntityProxy>(_id);
+
+				CanAccessIEntityId(entity);
+			}
+		}
+
+		[KnownBug("GH-2271")]
+		[Test]
+		public void ProxyInterfaceIdAccessFromDifferentInterfaces()
+		{
+			using (var session = OpenSession())
+			{
+				var entity = session.Load<IMultiIdProxy>(_id);
+
+				CanAccessIEntityId(entity);
+				CanAccessIEntity2Id(entity);
+			}
+		}
+
+		private void ThrowOnIEntityNameAccess(IEntity entity)
+		{
+			Assert.That(() => entity.Name, Throws.TypeOf<ObjectNotFoundException>(), "IEntity.Name access should lead to proxy initialization");
+		}
+
+		private void ThrowOnIEntityIdAccess(IEntity entity)
+		{
+			Assert.That(() => entity.Id, Throws.TypeOf<ObjectNotFoundException>(), "IEntity.Id access should lead to proxy initialization");
+		}
+
+		private void ThrowOnIEntity2IdAccess(IEntity2 entity)
+		{
+			Assert.That(() => entity.Id, Throws.TypeOf<ObjectNotFoundException>(), "IEntityId.Id access should lead to proxy initialization");
+		}
+
+		private void CanAccessIEntityId(IEntity entity)
+		{
+			Assert.That(() => entity.Id, Throws.Nothing, "Failed to access proxy IEntity.Id interface");
+			Assert.That(entity.Id, Is.EqualTo(_id));
+		}
+
+		private void CanAccessIEntity2Id(IEntity2 entity)
+		{
+			Assert.That(() => entity.Id, Throws.Nothing, "Failed to access proxy IEntity2.Id interface");
+			Assert.That(entity.Id, Is.EqualTo(_id));
+		}
+	}
+}
diff --git a/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/SubclassEntities.cs b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/SubclassEntities.cs
new file mode 100644
index 00000000000..5a5c54b9015
--- /dev/null
+++ b/src/NHibernate.Test/StaticProxyTest/InterfaceHandling/SubclassEntities.cs
@@ -0,0 +1,31 @@
+using System;
+
+namespace NHibernate.Test.StaticProxyTest.InterfaceHandling
+{
+	public interface ISubEntityProxy : IEntity
+	{
+		string AnotherName { get; set; }
+	}
+
+	public class EntityClassProxy : IEntity
+	{
+		public virtual Guid Id { get; set; }
+
+		public virtual string Name { get; set; }
+	}
+
+	class SubEntityInterfaceProxy : EntityClassProxy, ISubEntityProxy
+	{
+		public virtual string AnotherName { get; set; }
+	}
+
+	public interface IAnotherEntityProxy : IEntity
+	{
+		string AnotherName { get; set; }
+	}
+
+	class AnotherSubEntityInterfaceProxy : EntityClassProxy, IAnotherEntityProxy
+	{
+		public virtual string AnotherName { get; set; }
+	}
+}