Eh, I’ve never heard of this happening, so I’d suspect something in your browser, maybe having to do with Log On/Log Off? It would help us answer your question if we knew what kind of computer you have and what kind of software you’re using (Windows, Netscape, what?) Also, how many times has it done this? My other guess would be that it was just that you happened to click on an embedded link that didn’t “make” properly. Tell us which link(s) it was, in which thread(s)?
Does it only do this with links to SDMB threads, or to other websites, too?
Does it only do this with http: links, where it says “threadid=” etc., or does it do this with embedded links, where you see words in blue, like “This thread…”?