I noticed that the login cookies were not getting deleted in Safari during logout, and instead new, empty, ones were being created with a slightly different path. This diff fixed the problem for me:
--- ./wp-login.php Fri May 7 16:56:32 2004
+++ /Library/WebServer/BitsOfLight/Docs/wordpress/wp-login.php Fri May 14 15:38:17 2004
@@ -41,8 +41,8 @@ switch($action) {
case 'logout':
- setcookie('wordpressuser_'.$cookiehash);
- setcookie('wordpresspass_'.$cookiehash);
+ setcookie('wordpressuser_'.$cookiehash, " ", time() - 31536000, COOKIEPATH);
+ setcookie('wordpresspass_'.$cookiehash, " ", time() - 31536000, COOKIEPATH);
header('Expires: Wed, 11 Jan 1984 05:00:00 GMT');
header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-cache, must-revalidate');