Laravel 5.3 global scope dies when executing additional query

I need to add a global scope to a lot of models (I'm putting it into a trait) which will check if \Session::has('admin') and if it does it will query the 'admins' table, get the 'main_website' this admin belongs to and only show the results that belong to this website.

The problem is that the global scope dies after I start executing another query and I get error 500 with nothing in my logs.

Here is the trait:

trait MainWebsitable {

    public static function bootMainWebsitable()
    {
        static::addGlobalScope(new MainWebsitableScope);
    }

    public function scopeByWebsiteId($query, $id)
    {
        return $query->whereHas('mainWebsites', function ($query) use ($id) {
            $query->where('id', $id);
        });
    }
}

Here is the global scope:

class MainWebsitableScope implements Scope {
    public function apply(Builder $builder, Model $model) {
        if(\Session::has('admin')) {
            $adminId    = \Session::get('admin');
            $admin      = Admin::find($adminId);
            $website    = $admin->mainWebsites->first();
            if(isset($website)) {
                $builder->byWebsiteId($website->id);
            }
        }
    }

}

I've tried putting dd(\Session::get('admin')) after first if and it successfully returns the value saved in session. Then I've tried putting dd($admin) after Admin::find($adminId) and it returns the same 500 error as if I didn't have dd(). I've also tried doing another query (not querying the Admin model, but some other table) in that place and the same thing happens - 500 error with no explanation.

What am I doing wrong?

via Chebli Mohamed