diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Quantity.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Quantity.java
index fd3912594a..1fe0a11e02 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Quantity.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Quantity.java
@@ -1,6 +1,7 @@
 package org.hl7.fhir.dstu3.model;
 
 import java.math.BigDecimal;
+import java.util.ArrayList;
 
 /*
   Copyright (c) 2011+, HL7, Inc.
@@ -668,12 +669,16 @@ public String fhirType() {
       public Quantity copy() {
         Quantity dst = new Quantity();
         copyValues(dst);
+        return dst;
+      }
+
+      public void copyValues(Quantity dst) {
+        super.copyValues(dst);
         dst.value = value == null ? null : value.copy();
         dst.comparator = comparator == null ? null : comparator.copy();
         dst.unit = unit == null ? null : unit.copy();
         dst.system = system == null ? null : system.copy();
         dst.code = code == null ? null : code.copy();
-        return dst;
       }
 
       protected Quantity typedCopy() {
diff --git a/org.hl7.fhir.dstu3/src/test/java/org/hl7/fhir/dstu3/model/MedicationAdministrationCopyTest.java b/org.hl7.fhir.dstu3/src/test/java/org/hl7/fhir/dstu3/model/MedicationAdministrationCopyTest.java
new file mode 100644
index 0000000000..a1adeb2165
--- /dev/null
+++ b/org.hl7.fhir.dstu3/src/test/java/org/hl7/fhir/dstu3/model/MedicationAdministrationCopyTest.java
@@ -0,0 +1,40 @@
+package org.hl7.fhir.dstu3.model;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+
+import org.hl7.fhir.dstu3.formats.JsonParser;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class MedicationAdministrationCopyTest {
+
+  @DisplayName("Test MedicationAdministration copy")
+  @Test
+  public void test() throws IOException {
+      MedicationAdministration beforeCopy = createMedAdminWithDosageDurationExtension();
+      MedicationAdministration afterCopy = beforeCopy.copy();
+
+      System.out.println("---- BEFORE COPY (BEGIN)");
+      System.out.println(new JsonParser().composeString(beforeCopy));
+      System.out.println("---- BEFORE COPY (END)");
+      System.out.println();
+      System.out.println("---- AFTER COPY (BEGIN)");
+      System.out.println(new JsonParser().composeString(afterCopy));
+      System.out.println("---- AFTER COPY (END)");
+      assertTrue(beforeCopy.equalsDeep(afterCopy));
+  }
+
+  private static MedicationAdministration createMedAdminWithDosageDurationExtension() {
+      MedicationAdministration resource = new MedicationAdministration();
+      resource.setId("12345");
+      var dosage = new MedicationAdministration.MedicationAdministrationDosageComponent();
+      dosage.setDose((SimpleQuantity) new SimpleQuantity().setValue(40))
+              .addExtension(new Extension()
+                      .setUrl("http://duration")
+                      .setValue(new Duration().setValue(5340000)));
+      resource.setDosage(dosage);
+      return resource;
+  }
+}