you know i get this sometimes, but its not like its an "incorrect" tooltip or anything. I always assumed it was just an anomaly having to do with focus/timing issues. For instance sometimes ill have a vlc instance open watching something, pause it, refresh GW in my browser, then alt+tab back to vlc, hit space and F (play and fullscreen), then after a second the tooltip for the GW page will show (like as if im hovering over a topic in the board index, like your screenshot shows).
It doesn't happen with any regularity and I've never attempted to recreate it with any regularity as I just assumed it was an anomoly. I still think it's just an anomaly and you shouldn't worry about it.
yes coulombs are "germaine", did you learn that word at talk like a dick school?