Caddy (2.8.4) is hosting a PHP application through FastCGI (PHP-FPM) but for some reason the $_SERVER['SCRIPT_NAME'] does not contain the full path when I use the caddy handle_path config.

:80 {
    handle_path /subpath/* {
        # serve a PHP site through php-fpm:
        php_fastcgi localhost:9000 {
            root /var/www/html
        }
    }
}

When I visit:
www.domain.com/subpath/ I get:

$_SERVER['SCRIPT_NAME']=/index.php

But I would like to get /subpath/index.php

How should I change the caddyfile config to achieve this?