Description:
------------
I made a simple login page which redirects to another page if the userid and password is correct.

I verify the login by setting a session variable which is checked in the redirected page. If the session variable is not correct then the user is returned to the login page again.

The problem is this: 

if a user enters a correct password for the first then he is still being redirected back to the login page.

if the user enters the correct password again then he is directed to the next page.

During the session this problem doesn't occur again and the user can logoff and logon again without problems.

But only the first time he has to login twice which is very annoying.

Reproduce code:
---------------
login.php

$_SESSION['login'] = "Y";
	
echo "<script language='Javascript'>";
echo "document.location = 'http://www.somesite.com/index.php?team=999'";
echo "</script>";



index.php

if ($_SESSION['login'] != "Y")
{
	header("location: inloggen.php");
	exit ();
}
else
{
        echo "Welcome";
}



(i simplified the scripts)

Expected result:
----------------
I would expect that after the first succesfull login the script index.php would receive a session variable 'login' filled with a "Y"

Actual result:
--------------
After a succesfull login the script index.php receives session variable 'login' being empty and sends the user back to login.php

If the user enters the (same) correct data again then the second time script index.php DOES receive a "Y" in session variable 'login'