Flutter Streambuilder - where and orderBy combo doesn't work as reactive

In my code,

 Stream<List<Reminder>> getReminders() {
    return _db.collection('reminders').where('subject',isEqualTo: "SCM").orderBy('due',descending: true).snapshots().map((snapshot) => snapshot
        .docs
        .map((document) => Reminder.fromFirestore(document.data()))
        .toList());
  }

When I use where or orderBy separately, I can see the list is reactive, whenever I change something in Firestore, reflects immediately in the App in realtime. If I combine them like above, the app doesn't react to the change in realtime. What am I doing wrong?

Thanks.