wrong csrf cookie name?

[eluser]coolgeek[/eluser]
I'm setting my csrf cookie and token in config.php as follows:

Code:

$config['csrf_token_name'] = 'csrf_token';
$config['csrf_cookie_name'] = 'csrf_cookie';

On my dev site, everything works fine. When I view the cookies on my prod site, the cookie is named ci_csrf_token. Why isn't it named csrf_token?

Other cookie config (with domain name changed, but structurally representative).

Code:

$config['cookie_prefix']    = "";
$config['cookie_domain']    = ".mydomain.com";
$config['cookie_path']      = "/";
$config['cookie_secure']    = FALSE;

Thanks