Bug with session

I have two scripts:


1.phtml
<?
session_start();
session_register("vara");
session_register("varb");

$vara="Value A";
$varb="Value B";

echo "Goto <A href='2.phtml?".SID."'>page 2</a>";
?>


2.phtml
<?
$varb="No Value";

session_start();
session_register("vara");

echo "vara=".$vara."<BR>";
echo "varb=".$varb."<BR>";

?>

When I run page 1.phtml, then goto 2.phtml - in result I get:
vara=Value A
varb=Value B

This is bug! 
$varb must be "No value".

Vadim Tkachenko.