Route does not work with procent encoding

  1. frontend\views\layouts\main.php


                 $menuItems = [

                   ['label' => 'English', 'url' => ['/site/setlang&lang=en-US']],

                   ['label' => 'Deutsch', 'url' => ['/site/setlang&lang=de-DE']],

                   ['label' => '中文',  'url' => ['/site/setlang&lang=zh-CN']],


the url in the browser: index.php?r=site%2Fsetlang%26lang%3Dde-DE

   erro: Not Found (#404)

      the problem is suposted to be the procent encoding %26 and %3D. 

The %2F works fine like: index.php?r=site%2Findex

  1. works fine with:

<a href = "index.php?r=site/setlang&lang=de-DE" >Deutsch</a>

in the browser, url: index.php?r=site/setlang&lang=de-DE

I would say, it a bug, because yii interpretet the %26 not to & and %3d not to = respectively.