diff --git a/Tests/Linq/Tools/EntityServices/IdentityMapTests.cs b/Tests/Linq/Tools/EntityServices/IdentityMapTests.cs
index 2c53e2fa91..6214cec5f6 100644
--- a/Tests/Linq/Tools/EntityServices/IdentityMapTests.cs
+++ b/Tests/Linq/Tools/EntityServices/IdentityMapTests.cs
@@ -121,7 +121,7 @@ public async Task CompiledQueryTest()
 			var result1 = await query(db, default);
 			var result2 = await query(db, default);
 
-			Assert.That(result2[0], Is.SameAs(result1[0]));
+			Assert.That(result1[0], Is.SameAs(result2[0]));
 		}
 	}
 }
diff --git a/Tests/Linq/UserTests/Issue4390Tests.cs b/Tests/Linq/UserTests/Issue4390Tests.cs
new file mode 100644
index 0000000000..3bbfe7f863
--- /dev/null
+++ b/Tests/Linq/UserTests/Issue4390Tests.cs
@@ -0,0 +1,68 @@
+using System.Linq;
+
+using LinqToDB;
+using LinqToDB.Mapping;
+using NUnit.Framework;
+
+using System;
+
+using FluentAssertions;
+
+namespace Tests.UserTests
+{
+	[TestFixture]
+	public class Issue4390Tests : TestBase
+	{
+		[Table]
+		public class InfeedAdviceDTO
+		{
+			[Column] public int Id { get; set; }
+		}
+
+		[Table]
+		public class InventoryResourceDTO
+		{
+			[Column] public int InfeedAdviceID { get; set; }
+		}
+		public class MlogCombined1
+		{
+			public InfeedAdviceDTO? InfeedAdvice { get; set; }
+
+			public int? Count { get; set; }
+		}
+
+		public class MlogCombined2
+		{
+			public MlogCombined1? MlogCombined1 { get; set; }
+		}
+
+		[Test]
+		public void Issue4390Test([IncludeDataSources(TestProvName.AllSQLite)] string context)
+		{
+			using (var db = GetDataContext(context))
+			using (db.CreateLocalTable<InfeedAdviceDTO>())
+			using (db.CreateLocalTable<InventoryResourceDTO>())
+			{
+				db.Insert(new InventoryResourceDTO() { InfeedAdviceID = 1 });
+				db.Insert(new InfeedAdviceDTO() { Id = 1 });
+
+				var irs = from ir in db.GetTable<InventoryResourceDTO>() select ir;
+
+				var qry = from infeed in db.GetTable<InfeedAdviceDTO>()
+								join inventory in db.GetTable<InventoryResourceDTO>() on infeed.Id equals inventory.InfeedAdviceID
+								select new MlogCombined2
+								{
+									MlogCombined1 = new MlogCombined1
+									{
+										InfeedAdvice = infeed,
+										Count = irs.Count(x => x.InfeedAdviceID == infeed.Id),
+									}
+								};
+
+				var count = qry.Where(x => x.MlogCombined1 != null).Count();
+
+				count.Should().Be(1);
+			}
+		}
+	}
+}