diff --git a/staging/src/k8s.io/apimachinery/pkg/runtime/converter.go b/staging/src/k8s.io/apimachinery/pkg/runtime/converter.go
index b10fe4858bf..f6f7c10de62 100644
--- a/staging/src/k8s.io/apimachinery/pkg/runtime/converter.go
+++ b/staging/src/k8s.io/apimachinery/pkg/runtime/converter.go
@@ -411,7 +411,8 @@ func (c *unstructuredConverter) ToUnstructured(obj interface{}) (map[string]inte
 	var u map[string]interface{}
 	var err error
 	if unstr, ok := obj.(Unstructured); ok {
-		u = DeepCopyJSON(unstr.UnstructuredContent())
+		// UnstructuredContent() mutates the object so we need to make a copy first
+		u = unstr.DeepCopyObject().(Unstructured).UnstructuredContent()
 	} else {
 		t := reflect.TypeOf(obj)
 		value := reflect.ValueOf(obj)
diff --git a/staging/src/k8s.io/apimachinery/pkg/runtime/converter_test.go b/staging/src/k8s.io/apimachinery/pkg/runtime/converter_test.go
index 1e9515102cf..7820b8cefd8 100644
--- a/staging/src/k8s.io/apimachinery/pkg/runtime/converter_test.go
+++ b/staging/src/k8s.io/apimachinery/pkg/runtime/converter_test.go
@@ -135,7 +135,7 @@ func doRoundTrip(t *testing.T, item interface{}) {
 		return
 	}
 	unmarshalledObj := reflect.New(reflect.TypeOf(item).Elem()).Interface()
-	err = json.Unmarshal(data, &unmarshalledObj)
+	err = json.Unmarshal(data, unmarshalledObj)
 	if err != nil {
 		t.Errorf("Error when unmarshaling to object: %v", err)
 		return
@@ -169,6 +169,38 @@ func TestRoundTrip(t *testing.T) {
 	testCases := []struct {
 		obj interface{}
 	}{
+		{
+			obj: &unstructured.UnstructuredList{
+				Object: map[string]interface{}{
+					"kind": "List",
+				},
+				// Not testing a list with nil Items because items is a non-optional field and hence
+				// is always marshaled into an empty array which is not equal to nil when unmarshalled and will fail.
+				// That is expected.
+				Items: []unstructured.Unstructured{},
+			},
+		},
+		{
+			obj: &unstructured.UnstructuredList{
+				Object: map[string]interface{}{
+					"kind": "List",
+				},
+				Items: []unstructured.Unstructured{
+					{
+						Object: map[string]interface{}{
+							"kind": "Pod",
+						},
+					},
+				},
+			},
+		},
+		{
+			obj: &unstructured.Unstructured{
+				Object: map[string]interface{}{
+					"kind": "Pod",
+				},
+			},
+		},
 		{
 			obj: &unstructured.Unstructured{
 				Object: map[string]interface{}{
@@ -260,7 +292,7 @@ func TestRoundTrip(t *testing.T) {
 // produces the same object.
 func doUnrecognized(t *testing.T, jsonData string, item interface{}, expectedErr error) {
 	unmarshalledObj := reflect.New(reflect.TypeOf(item).Elem()).Interface()
-	err := json.Unmarshal([]byte(jsonData), &unmarshalledObj)
+	err := json.Unmarshal([]byte(jsonData), unmarshalledObj)
 	if (err != nil) != (expectedErr != nil) {
 		t.Errorf("Unexpected error when unmarshaling to object: %v, expected: %v", err, expectedErr)
 		return
@@ -465,11 +497,10 @@ func TestUnrecognized(t *testing.T) {
 		},
 	}
 
-	for i := range testCases {
-		doUnrecognized(t, testCases[i].data, testCases[i].obj, testCases[i].err)
-		if t.Failed() {
-			break
-		}
+	for _, tc := range testCases {
+		t.Run(tc.data, func(t *testing.T) {
+			doUnrecognized(t, tc.data, tc.obj, tc.err)
+		})
 	}
 }
 
diff --git a/test/e2e/apimachinery/garbage_collector.go b/test/e2e/apimachinery/garbage_collector.go
index 25960cdb3ad..e52ca37348b 100644
--- a/test/e2e/apimachinery/garbage_collector.go
+++ b/test/e2e/apimachinery/garbage_collector.go
@@ -919,8 +919,8 @@ var _ = SIGDescribe("Garbage collector", func() {
 				"kind":       definition.Spec.Names.Kind,
 				"metadata": map[string]interface{}{
 					"name": dependentName,
-					"ownerReferences": []map[string]string{
-						{
+					"ownerReferences": []interface{}{
+						map[string]interface{}{
 							"uid":        string(persistedOwner.GetUID()),
 							"apiVersion": apiVersion,
 							"kind":       definition.Spec.Names.Kind,