Auto-Routing don't work with 4.4.0

Hello,
It seems Auto-Routing doesn't work as before with CI 4.4.0 and new Config\Routing.php file.
We have to add \\ at the end of $defaultNamespace if we don't want to have a 404 page with method unavailable.
Before, when we use $routes->setDefaultNamespace in Config\App.php file, it add automatically \\ at the end of the string.
Is it a bug or a feature ? Or me perhaps...

Max