Running my sample script with the loop set up to 65534 times will run without corrupting the array $a.  If you run it as 65535 times or more, the array is corrupted, and the value of $b becomes an array, which then causes the following warnings to be generated:

PHP Warning:  Illegal offset type in /home/web/dev/docs/lookup/bug.php on line 9

Obviously the foreach and array assignments should not be corrupting the contents of array $a.

Sample script:

<script language="php">
$a = array(1);
foreach($a as $b)
{
  for($c = 0; $c < 65535; $c++)
  {
    $d = 1;
    $e[$d][] = array($b, $c);
    $f[$b][$c][] = $d;
  }
}
</script>
done

Configure command:

./configure \
--with-mysql=/usr/local/mysql \
--with-apxs=/usr/local/apache/bin/apxs \
--enable-ftp \
--enable-track-vars \
--enable-versioning \
--with-zlib