diff --git a/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/DotNetNameResolver.java b/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/DotNetNameResolver.java
index 9afc90b1e..5f23f8e26 100644
--- a/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/DotNetNameResolver.java
+++ b/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/DotNetNameResolver.java
@@ -451,6 +451,13 @@ public String isSetMethodForStructureMember(final MemberShape memberShape) {
         return "IsSet%s".formatted(classPropertyForStructureMember(memberShape));
     }
 
+    /**
+     * Returns the name of the given member shape's IsSet member
+     */
+    public String isSetMemberForStructureMember(final MemberShape memberShape) {
+        return "Is%sSet".formatted(classPropertyForStructureMember(memberShape));
+    }
+
     /**
      * Returns the name of the class property fur use as a variable name, i.e. the first letter is lower case
      */
diff --git a/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/TypeConversionCodegen.java b/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/TypeConversionCodegen.java
index a103b79cd..9e2102041 100644
--- a/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/TypeConversionCodegen.java
+++ b/codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydotnet/TypeConversionCodegen.java
@@ -479,6 +479,24 @@ private String generateConstructorArg(final MemberShape memberShape) {
                 nameResolver.classPropertyForStructureMember(memberShape));
     }
 
+    // return false if this struct/member is one of the special ones with a IsXxxSet member
+    public boolean IsNormal(final MemberShape memberShape)
+    {
+	String parent = memberShape.getId().getName();
+	String member = nameResolver.classPropertyForStructureMember(memberShape);
+	if (parent.equals("ScanInput")) {
+	    if (member.equals("TotalSegments") ||
+		member.equals("Segment") ||
+		member.equals("Limit")) {
+		return false;
+	    }
+	}
+        if (parent.equals("QueryInput") && member.equals("Limit")) {
+	    return false;
+	}
+	return true;
+   }
+
     /**
      * Returns:
      * "type varName = value.IsSetPropertyName() ? value.PropertyName : (type) null;"
@@ -488,14 +506,25 @@ public TokenTree generateExtractOptionalMember(final MemberShape memberShape) {
         final String varName = nameResolver.variableNameForClassProperty(memberShape);
         final String propertyName = nameResolver.classPropertyForStructureMember(memberShape);
         if (AwsSdkNameResolverHelpers.isInAwsSdkNamespace(memberShape.getId())) {
-            return TokenTree.of(
-                type,
-                varName,
-                "= value.%s != null".formatted(propertyName),
-                "? value.%s :".formatted(propertyName),
-                "(%s) null;".formatted(type)
-            );
-        } else {
+	    if (IsNormal(memberShape)) {
+		return TokenTree.of(
+                   type,
+                   varName,
+                   "= value.%s != null".formatted(propertyName),
+                   "? value.%s :".formatted(propertyName),
+                   "(%s) null;".formatted(type)
+                );
+	    } else {
+		final String isSetMethod = nameResolver.isSetMemberForStructureMember(memberShape);
+		return TokenTree.of(
+                   type,
+                   varName,
+                   "= value.%s".formatted(isSetMethod),
+                   "? value.%s :".formatted(propertyName),
+                   "(%s) null;".formatted(type)
+		);
+	    }
+      } else {
             final String isSetMethod = nameResolver.isSetMethodForStructureMember(memberShape);
             return TokenTree.of(
                 type,