Plugin Trait don't get template

Plugins
1

My plugin have a Trait “Admin” for the common actions used in backend:

<?php
namespace AdminTrait\AdminTrait;    
trait AdminTrait
{
	public function index() {
    	$this->autoRender = false;
		$records = $this->{$this->name}->find();
		$this->set('adminOptions',$this->adminOptions);
		$this->set('records', $this->paginate($records));
 
		if(in_array('index', $this->useAdmin)) {
            return $this->render('AdminTrait.Default/index');
		}
	}
}

Controller:

<?php
namespace App\Controller\Admin;
use App\Controller\Admin\AppController;
class FooController extends AppController
{
    use \AdminTrait\AdminTrait\AdminTrait; 
}

In my controller set to use the trait and all works fine if i go to:
http://mysite/admin/Foo/index
The trait method is trigged but cake raise an Missing Template Exception:
/var/www/mysite/Template/Admin/Foo/Default/index.ctp
Why return $this->render(‘AdminTrait.Default/index’); is not fine?