diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/conv40_50/StructureMap40_50.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/conv40_50/StructureMap40_50.java
index ee3be5756..f525cb558 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/conv40_50/StructureMap40_50.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/conv40_50/StructureMap40_50.java
@@ -3,6 +3,7 @@ package org.hl7.fhir.convertors.conv40_50;
 
 import org.hl7.fhir.convertors.VersionConvertor_40_50;
 import org.hl7.fhir.exceptions.FHIRException;
+import org.hl7.fhir.r4.model.StructureMap.StructureMapGroupTypeMode;
 
 import java.util.stream.Collectors;
 
@@ -220,8 +221,11 @@ public class StructureMap40_50 extends VersionConvertor_40_50 {
             tgt.setNameElement(convertId(src.getNameElement()));
         if (src.hasExtends())
             tgt.setExtendsElement(convertId(src.getExtendsElement()));
-        if (src.hasTypeMode())
+        if (src.hasTypeMode()) {
             tgt.setTypeModeElement(convertStructureMapGroupTypeMode(src.getTypeModeElement()));
+        } else {
+          tgt.setTypeMode(StructureMapGroupTypeMode.NONE);          
+        }
         if (src.hasDocumentation())
             tgt.setDocumentationElement(convertString(src.getDocumentationElement()));
         for (org.hl7.fhir.r5.model.StructureMap.StructureMapGroupInputComponent t : src.getInput()) tgt.addInput(convertStructureMapGroupInputComponent(t));