Session lost AJAX CI 3.x

Hello
Yes It seems Codeigniter has fixed this issue in the Session.php Library!! But I have experienced something similar but in a different manner! When you perform the first ajax request to the server everything goes fine!! When you execute the same ajax immediately after the first one has completed you experience a lagging and some NOT ALL of the session variables get lost!!

But If you wait for a minimum of 5-10sec, then perform the same ajax request everything goes fine!! I think there's a serious issue that still going on with Codeigniter Session!!

I have Just upgraded From Codeigniter 2 to 3 successfully! And am using the files driver session with heavy ajax request!!
Funny enough!! Some of my ajax requests works just fine, except the ones from ones who's links are within table tags <td></td>!! But they both use the same ajax request Function.

So I have failed to understand whether its codeignitor!! Or something to do with AJAX!!

Another thing is that when i take the url of the same ajax request that has issues and post it on the browser url tab everything goes fine!

I have seen other posts including the codeigniter documentation itself that we should use the session_write_close(); but going through the Session Class itself seems like Codeignitor 3 runs this function already!!

I have also realized that for firefox it is much better! The session variables are all intact! but the extra delay still exists on the second ajax call!!
I am using Xampp on windows offline!

And also when i upload the project on the server online!! Its works Fine!! I am surely left with nothing to say!!

Kindly assist on this!!
Regards!