Description:
------------
php -v gives:
PHP 5.0.3 (cli) (built: Dec 19 2004 15:05:29)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.0.3, Copyright (c) 1998-2004 Zend Technologies
    with Turck MMCache v2.4.6, Copyright (c) 2002-2003 TurckSoft, St. Petersburg, by Dmitry Stogov
    with Zend Extension Manager v1.0.7, Copyright (c) 2003-2004, by Zend Technologies
    with Zend Debugger v3.5.2, Copyright (c) 1999-2004, by Zend Technologies
Configure line:
'./configure' '--prefix=/usr' '--sysconfdir=/etc' '--with-gmp' '--with-mysql' '--with-bz2' '--with-gd' '--with-zlib' '--with-zlib-dir=/usr' '--with-apxs2=/usr/sbin/apxs'
/usr/sbin/httpd -v
Server version: Apache/2.0.49
Server built:   Jul 28 2004 17:29:16

The bug only occures, when you open the file with a browser on the server (apache). When you start the file with php -q or debug it with Zend Studio, the bug does not occur.

Reproduce code:
---------------
<?php
$x = array("1" => "5", "2" => "7", "3" => "9");
$y = array("2" => "1");
$i=2;
$x[$i] -= $y[$i];
print_r($x);
?>

Expected result:
----------------
Array
(
    [1] => 5
    [2] => 6
    [3] => 9
)

Actual result:
--------------
6