Replying to NS suddenly drops my sessions after awhile?

In the past, I could login to NS and say logged in for as long as I want. (I'm one of those keep 10 tabs open at all times kind of people.) I never did the "Remember me" or anything like that before, but it just always kept my session alive.

Probably in the last 2 weeks or so, I've been noticing that my session is automatically dropped after some time. Every morning when I wake up I have to re-login and sometimes during the day depending on how long it's been.

Did you guys change something with the login? Maybe you stopped using cookies or increased the PHP session timeout? Just wondering what's up.

Thanks!