Index: Ringtoets/HeightStructures/test/Ringtoets.HeightStructures.Plugin.Test/FileImporters/HeightStructureUpdateDataStrategyTest.cs
===================================================================
diff -u -rb96176ebd8a361085b738455d0882b2ab8e26ac3 -rbc752890b4f52991a673a59c089db400be0e6fc3
--- Ringtoets/HeightStructures/test/Ringtoets.HeightStructures.Plugin.Test/FileImporters/HeightStructureUpdateDataStrategyTest.cs	(.../HeightStructureUpdateDataStrategyTest.cs)	(revision b96176ebd8a361085b738455d0882b2ab8e26ac3)
+++ Ringtoets/HeightStructures/test/Ringtoets.HeightStructures.Plugin.Test/FileImporters/HeightStructureUpdateDataStrategyTest.cs	(.../HeightStructureUpdateDataStrategyTest.cs)	(revision bc752890b4f52991a673a59c089db400be0e6fc3)
@@ -442,7 +442,7 @@
 
             HeightStructure readAffectedStructure = new TestHeightStructure(affectedId, "New name");
             HeightStructure readUnaffectedStructure = new TestHeightStructure(unaffectedId, unaffectedStructureName);
-            
+
             // Call
             IEnumerable<IObservable> affectedObjects = strategy.UpdateStructuresWithImportedData(targetDataCollection,
                                                                                                  new[]
@@ -460,7 +460,7 @@
             HeightStructure inputParametersUnaffectedStructure = unaffectedCalculation.InputParameters.Structure;
             Assert.AreSame(unaffectedStructure, inputParametersUnaffectedStructure);
             AssertHeightStructures(readUnaffectedStructure, inputParametersUnaffectedStructure);
-            
+
             CollectionAssert.AreEquivalent(new IObservable[]
             {
                 affectedCalculation,
@@ -470,6 +470,58 @@
         }
 
         [Test]
+        public void UpdateStructuresWithImportedData_CalculationWithSameReference_OnlyReturnsDistinctCalculation()
+        {
+            // Setup
+            const string affectedId = "affectedId";
+            var affectedStructure = new TestHeightStructure(affectedId, "Old name");
+            var affectedCalculation = new TestHeightStructuresCalculation
+            {
+                InputParameters =
+                {
+                    Structure = affectedStructure
+                },
+                Output = new TestStructuresOutput()
+            };
+
+            var failureMechanism = new HeightStructuresFailureMechanism
+            {
+                CalculationsGroup =
+                {
+                    Children =
+                    {
+                        affectedCalculation,
+                        affectedCalculation
+                    }
+                }
+            };
+
+            StructureCollection<HeightStructure> structures = failureMechanism.HeightStructures;
+            structures.AddRange(new[]
+            {
+                affectedStructure
+            }, sourceFilePath);
+
+            var structureToUpdateFrom = new TestHeightStructure(affectedId, "New name");
+
+            var strategy = new HeightStructureUpdateDataStrategy(failureMechanism);
+
+            // Call
+            IEnumerable<IObservable> affectedObjects = strategy.UpdateStructuresWithImportedData(structures,
+                                                                                                 new[]
+                                                                                                 {
+                                                                                                     structureToUpdateFrom
+                                                                                                 }, sourceFilePath);
+            // Assert
+            CollectionAssert.AreEquivalent(new IObservable[]
+            {
+                structures,
+                affectedCalculation,
+                affectedCalculation.InputParameters
+            }, affectedObjects);
+        }
+
+        [Test]
         public void UpdateStructuresWithImportedData_SectionResultWithStructureImportedStructureWithSameId_UpdatesCalculation()
         {
             // Setup