I've noticed that whenever I choose "Last two months" in the dropdown date selector menu on the active topic page, after a few seconds it turns blank. I've attached a little video of me doing this.. Sorry for the horrible quality, it was originally a .ogg created by gtk-recordmydesktop but I used ffmpeg to convert it to an avi. The quality wasn't that great, but you can see what's going on.
Maybe that option should be removed?