Description:
------------
Randomly, the cookies send back random values to the server, values different than those set the previous page load.

I use session auto start on php.ini. PHP runs on Apache 2.

Reproduce code:
---------------
a, b, locka and lockb are cookies set with setcookie(<name>, <value>, 0, "/");

if($somevar == "lock") {
  echo "lock";
  Set cookies locka and lockb with the values of cookies a and b respectively.
} else if($somevar == "random") {
  echo "random";
  Delete locka and lockb, and give a random value to a.
} else {
  echo "none";
  if(locka not set) Set random value to a.
}
if (b not set) Set random value to b.

Enter pages in that order:
www.domain.com/page/
www.domain.com/page/lock/
www.domain.com/page/random/
www.domain.com/page/lock/

(The if logic works, this is not a case of $somevar holding an incorrect value.)

Expected result:
----------------
www.domain.com/page/
received cookies: none
output: none
sent cookies: a with value x; b with value y

www.domain.com/page/lock/
received cookies: a with value x
output: lock
sent cookies: lock a = x; lock b = y

www.domain.com/page/random/
received cookies: a with value x; b with value y; locka with value x; lockb with value y
output: random
sent cookies: delete lock a; delete lock b; a = z

www.domain.com/page/lock/
received cookies: a with value z; b with value y
output: lock
sent cookies: lock a = z; lock b = y

Actual result:
--------------
Everything as expected except the last page load: The cookie received isn't a = z, it is a = q, I mean, another value. The server then sends "lock a = q" following the logic.

PHPSESSID is received and reset on every page load.
1.
HTTP Request Headers
HTTP Request 	GET /page/ HTTP/1.1
User-Agent 	Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8.0.2) Gecko/20060308 Firefox/1.5.0.2

HTTP Response Headers
Set-Cookie 	PHPSESSID=3fo392aek7m274550d9oppqdo6; path=/
Expires 	Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control 	no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma 	no-cache
Set-Cookie 	a=3; path=/
Set-Cookie 	b=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52; path=/




2. (The request is as expected)
HTTP Request Headers
HTTP Request 	GET /page/lock/ HTTP/1.1
a=3;
b=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52

(We lock the values of a and b)
HTTP Response Headers
Set-Cookie 	locka=3; path=/
Set-Cookie 	lockb=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52; path=/




3.(The request is as expected)
HTTP Request Headers
HTTP Request 	GET /page/random/ HTTP/1.1
Cookie
a=3;
b=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52;
locka=3;
lockb=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52

(We delete the locked values and set a random value for a, this case 2)
HTTP Response Headers
Set-Cookie 	locka=deleted; expires=Sat, 16-Apr-2005 01:33:24 GMT; path=/
Set-Cookie 	lockb=deleted; expires=Sat, 16-Apr-2005 01:33:24 GMT; path=/
Set-Cookie 	a=2; path=/




4. (The request is not as expected, that value for 'a' had not even been used in the whole run -we are getting 1)
HTTP Request Headers
HTTP Request 	GET /page/lock/ HTTP/1.1
a=1;
b=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52

(We lock the received values, this case 1)
HTTP Response Headers
Set-Cookie 	locka=1; path=/
Set-Cookie 	lockb=91-5-177-39-4-61-87-25-1-42-0-50-64-5-164-52; path=/