Well, we haven't changed the software in a while...

There's sometimes been a timestamp/multiple post problem with navigating the boards using a browser's back/forward buttons, depending on what browser you're using.

It sounds like your browser is caching some pages, while loading others. If the page is cached, then there probably won't be a change in the lightbulbs. But if you open the page in a new window, then that may cause the system to get the latest stamp info.

Instead of using Back/Forward, have you tried using the built-in navigation that UBB provides? The Forum hierarchy navigation at the top of the screen...

I don't think that'll help the problem you;re having with opening new threads in new windows, but it might solve the other issue you brought up.