Laravel json() response returning values twice

I have set up a model User and I created a controller to get some values:

<?php 

namespace App\Http\Controllers;

use Dingo\Api\Routing\Helpers;
use Illuminate\Routing\Controller;

use App\Models\User;

class UserController extends Controller
{

    use Helpers;

    public function index()
    {
        $users = User::all();

        return $users;
    }
}

But when I run this, the json value is returned twice:

{
  "users": [
    {
      "0": "Firstname Lastname",
      "1": "Accusantium commodi repellat quia eos. Cumque debitis qui deserunt aspernatur harum vitae aut.",
      "2": 1,
      "3": "2016-12-04 21:56:59",
      "4": "2016-12-04 21:56:59",
      "name": "Firstname Lastname",
      "profile": "Accusantium commodi repellat quia eos. Cumque debitis qui deserunt aspernatur harum vitae aut.",
      "house_id": 1,
      "created_at": "2016-12-04 21:56:59",
      "updated_at": "2016-12-04 21:56:59"
    },
}

But, a strange thing: the response above is when I have an empty $visible[] array in my User model. But when I set the $visible to contain, for example, name and profile both values are only displayed once. What is the problem here? Why is it showing up twice?

via Chebli Mohamed