diff --git a/types/dynamic/dynamic.go b/types/dynamic/dynamic.go
index b8f01f2774..bb5b0d789c 100644
--- a/types/dynamic/dynamic.go
+++ b/types/dynamic/dynamic.go
@@ -204,8 +204,8 @@ func ExtractCustomAttributes(v interface{}, msg []byte) ([]byte, error) {
 		return nil, err
 	}
 	objectStarted := false
-	for field, value := range anys {
-		_, ok := fields[field]
+	for _, any := range sortAnys(anys) {
+		_, ok := fields[any.Name]
 		if ok {
 			// Not a custom attribute
 			continue
@@ -216,8 +216,8 @@ func ExtractCustomAttributes(v interface{}, msg []byte) ([]byte, error) {
 		} else {
 			stream.WriteMore()
 		}
-		stream.WriteObjectField(field)
-		value.WriteTo(stream)
+		stream.WriteObjectField(any.Name)
+		any.WriteTo(stream)
 	}
 	if !objectStarted {
 		stream.WriteObjectStart()
diff --git a/types/dynamic/dynamic_test.go b/types/dynamic/dynamic_test.go
index 7ff73d3df1..425aaf0d07 100644
--- a/types/dynamic/dynamic_test.go
+++ b/types/dynamic/dynamic_test.go
@@ -1,6 +1,7 @@
 package dynamic
 
 import (
+	"encoding/json"
 	"reflect"
 	"testing"
 
@@ -94,6 +95,25 @@ func (m MyType) Get(name string) (interface{}, error) {
 	return GetField(m, name)
 }
 
+func (m MyType) MarshalJSON() ([]byte, error) {
+	return Marshal(m)
+}
+
+func (m *MyType) UnmarshalJSON(p []byte) error {
+	type __ MyType
+	var x __
+	if err := json.Unmarshal(p, &x); err != nil {
+		return err
+	}
+	*m = MyType(x)
+	custom, err := ExtractCustomAttributes(m, p)
+	if err != nil {
+		return err
+	}
+	m.custom = custom
+	return nil
+}
+
 func TestExtractEmptyCustomAttributes(t *testing.T) {
 	require := require.New(t)
 	assert := assert.New(t)
@@ -247,3 +267,14 @@ func TestQueryGovaluateComplex(t *testing.T) {
 	require.Nil(t, err)
 	require.Equal(t, true, result)
 }
+
+func TestMarshalUnmarshal(t *testing.T) {
+	data := []byte(`{"bar":null,"foo":"hello","a":10,"b":"c"}`)
+	var m MyType
+	err := json.Unmarshal(data, &m)
+	require.Nil(t, err)
+	assert.Equal(t, MyType{Foo: "hello", custom: []byte(`{"a":10,"b":"c"}`)}, m)
+	b, err := json.Marshal(m)
+	require.Nil(t, err)
+	assert.Equal(t, data, b)
+}