It's most likely due to a cache glitch in Firefox and/or upstream, such as an ISP proxy ... not spyware, etc.

Server glitches happen for sure with the boards, but they often appear as duplicate / extraneous subject lines and/or broken html.

In the screen-cap you posted, the html appears correct ... note the icons shown left of each message board topic are missing ... this further leads me to believe what you saw was most likely due to a client/ISP cache problem of some sort.

Thanks for posting the trouble report.

Ron