Maybe you have the same problem I was having: that Auth::user() is null when called from Scope apply() method. Calling it from the constructor does seem to work.. most of the time. I don't understand why it doesn't always work by either method, but so far, by using the constructor and the apply() as backup, it seems to work all of the time.

<?php namespace App\Scopes;

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Scope;
use Illuminate\Support\Facades\Auth;

class ShopScope implements Scope
{
    protected $user;

    /**
     * double try to get Auth::user because for unknown reason doesn't always work
     *
     * ShopScope constructor.
     */
    public function __construct()
    {
        $this->user = Auth::user();
    }

    public function apply(Builder $builder, Model $model)
    {
        $user = $this->user ?: Auth::user();

        //your code here
    }

}