flutter bug floatingLabelBehavior not obey InputDecorationTheme

main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        theme: ThemeData(
          inputDecorationTheme: InputDecorationTheme(
            floatingLabelBehavior: FloatingLabelBehavior.always,
            enabledBorder: OutlineInputBorder(),
          ),
        ),
      home: Scaffold(
        body: Container(
          padding: EdgeInsets.all(48.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              TextFormField(
                decoration: InputDecoration(
                  labelText: 'Label text',
                  hintText: 'Hint text',
                ),
              ),
            ], 
          ),
        ),
      ),
    );
  }
}