No I am not. It does the same thing on any device I am using. For example I logged in to see some pictures in threads I was reading. I went to another thread and decided to reply to that thread. In the few minutes (less than 5) it took me to type, when I hit reply, it took me to the login page before it would post.
What browser are you using??? I am using firefox and it keeps me logged in every time I am on the site. Unless I clear out the browser I don't have to sign back in. At least for days or weeks.