diff --git a/api/krusty/duplicatekeys_test.go b/api/krusty/duplicatekeys_test.go
index c87cd6c34..a8ba67238 100644
--- a/api/krusty/duplicatekeys_test.go
+++ b/api/krusty/duplicatekeys_test.go
@@ -43,5 +43,5 @@ spec:
 	m := th.Run(".", th.MakeDefaultOptions())
 	_, err := m.AsYaml()
 	require.Error(t, err)
-	assert.Contains(t, err.Error(), "mapping key \"env\" already defined")
+	assert.Contains(t, err.Error(), "key \"env\" already set in map")
 }
diff --git a/kyaml/yaml/rnode.go b/kyaml/yaml/rnode.go
index bb929059f..c766565b1 100644
--- a/kyaml/yaml/rnode.go
+++ b/kyaml/yaml/rnode.go
@@ -17,6 +17,7 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/sliceutil"
 	"sigs.k8s.io/kustomize/kyaml/utils"
 	"sigs.k8s.io/kustomize/kyaml/yaml/internal/k8sgen/pkg/labels"
+	k8syaml "sigs.k8s.io/yaml"
 )
 
 // MakeNullNode returns an RNode that represents an empty document.
@@ -983,20 +984,11 @@ func (rn *RNode) MarshalJSON() ([]byte, error) {
 		return nil, err
 	}
 
-	if yNode.Kind == SequenceNode {
-		var a []interface{}
-		if err := Unmarshal([]byte(s), &a); err != nil {
-			return nil, err
-		}
-		return json.Marshal(a)
+	b, err := k8syaml.YAMLToJSONStrict([]byte(s))
+	if err != nil {
+		return nil, errors.Wrap(err)
 	}
-
-	m := map[string]interface{}{}
-	if err := Unmarshal([]byte(s), &m); err != nil {
-		return nil, err
-	}
-
-	return json.Marshal(m)
+	return b, nil
 }
 
 // UnmarshalJSON overwrites this RNode with data from []byte.