For example, I entered "Indian" on the Pennsylvania boards and got a page of some posts referring to this topic. I clicked on one thread and after reading one message, clicked on the "back" button on the top of my screen (toolbar). The resulting page read,
"Warning: Page has Expired The page you requested was created using information you submitted in a form. This page is no longer available. As a security precaution, Internet Explorer does not automatically resubmit your information for you.
To resubmit your information and view this Web page, click the Refresh button."
After clicking on the refresh button, the previous page WAS displayed. This error (and the need for clicking on the refresh button) did not occur when I went through this process on the "User Help" board.
EDITED post ... I just hit the back button on the user board and got the error message I referred to. Only way to get the previous page of messages displayed was to hit the "refresh" button.
NEW EDITED post ... Now the back button displays the previous threads on the "user help" board. Some sequence of steps produces these results. They are consist. I don't know why one works and the other doesn't.