some problem about Tabs shared cookies

Hi:

    I occure some problem about new Tabs in IE8.

    I login my webSite, and then open  tabs more than 22 , and then logout, my webSite will kickoff all Tabs to login html

   my  problem is:

   when I reLogin in one of tabs, send /authenticate.action to the server, login success.

  I watch the action through Fiddler2.

 the request include cookie: 

Cookie
JSESSIONID=1ux05tt0mjbs71wzdbakdwivqn

  and the response is set new cookie value:

Set-Cookie: JSESSIONID=1o2ugsgnxcygdmlxvsbu4y9gr;Path=/

  but some of another pages' cookie do not change, I see the cookie throuth F12

the cookie is retain :1ux05tt0mjbs71wzdbakdwivqn.

the cookies do not share between some tabs.

some body has meet the same problem?

As I known, IE8' tabs share the cookie, and I create few tabs, these tabs share cookies.

but if I create too more tabs, it does not share ?

why?