WordPress wp_verify_nonce behaving differently on Chrome and Safari?

I am confused beyond reason about the following behavior in a WordPress application. In the operative template, the following PHP appears:

<?php 
  $email = $_GET['email'];
  $result = wp_verify_nonce(
    $_GET['_wpnonce'],
    'reset-'.$email
  );
?>

But the identical URI,

http://www.server.com/reset-my-account/?action=reset&email=andrew%40digivino.com&_wpnonce=2531fe2151

yields a different $result, depending whether the URI is delivered from Chrome or from Safari.

Any guesses why?