route group, only first one works

I am trying to group my routes in order to improve the readability.
But if I add a group, only the first one in the group seems to work.

PHP Code:

$routes->group('cms', static function ($routes) {
    $routes->get('/', [Dashboard::class, 'index']);
    $routes->get('/login', [Authentication::class, 'login']);
});

//$routes->get('/cms/', [Dashboard::class, 'index']);
//$routes->get('/cms/login', [Authentication::class, 'login']); 


When I un-escape the original routes, all works well, but in the group only /cms works.
Am I expecting something other than designed?
https://site/cms/login ends up with:

Code:

404 - File Not Found
Can't find a route for 'get: cms/login'.

remove / (backlash)
$routes->get('login', [Authentication::class, 'login']);

Yes, that did the trick....
Thanks!