Error in backoffice exporadically, without solution

[Moleco]

Does anyone know why from time to time I get this error in the backoffice, only in frot it works fine. It comes up on its own, without doing anything strange.

 

Fatal error: Uncaught Symfony\Component\DependencyInjection\Exception\InvalidArgumentException: Expected to find class "PrestaShopBundle\Controller\Admin\Sell\index" in file "/home/xxxxxxx/public_html/src/PrestaShopBundle/Controller/Admin/Sell/index.php" while importing services from resource "/home/xxxxxxx/public_html/app/../src/PrestaShopBundle/Controller/*", but it was not found! Check the namespace prefix used with the resource. in /home/xxxxxxx/public_html/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php:157 Stack trace: #0 /home/xxxxxxx/public_html/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php(57): Symfony\Component\DependencyInjection\Loader\FileLoader->findClasses('PrestaShopBundl...', '/home/prestaser...', '/home/prestaser...') #1 /home/xxxxxxx/public_html/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php(578): Symfony\Component\DependencyInjection\Loader\FileLoader->register in /home/xxxxxxx/public_html/vendor/symfony/symfony/src/Symfony/Component/Config/Loader/FileLoader.php on line 168

[Moleco]

ohhh wow the same thing just happened to me again using version 1.7.7.2 completely clean, it was supposed to be fixed in this version. XD