query_vars hook: custom vars not registering

Hi there,

in my theme’s functions.php I use

function add_custom_query_vars($vars) {
  $vars[] = "tdhm";
  $vars[] = "tdht";
  return $vars;
}
add_filter('query_vars', 'add_custom_query_vars');

to register the two custom vars “tdhm” and “tdht”.

When I try to access them lateron fromn my page’s template

if(isset($wp_query->query_vars['tdhm'])) {
  $email = urldecode($wp_query->query_vars['tdhm']);
}

if(isset($wp_query->query_vars['tdht'])) {
  $token = urldecode($wp_query->query_vars['tdht']);
}

they are always empty.

I looked up the results of var_dump($wp_query->query_vars); and they are nowhere to be found. What am I doing wrong? I could not find anything on this issue within Codex and I have used this function before in other WordPress versions without any problems.

Best regards, Mathias