Route error when the value is greater than 9

My configuration:

Code:

$routes->group('members', ['namespace' => 'App\Controllers'], function ($routes) {
    $routes->get('/', 'Members::index');
    $routes->add('(:any).(:num)/aaa', 'Members::aaa/$1.$2');
});

My link: https://domain.com/members/abcdef.13/aaa
When "(:num)" is less than 10, it's true.
When "(:num)" is greater than or equal to 10, it's false.