Comment 10 for bug 387319

I have the same behavior in Karmic with the latest updates. There is an Ubuntu forums post about it here:
http://ubuntuforums.org/showthread.php?t=1329426

This is a more serious bug than one might think -- to the casual user it can look like an entire directory of pdf files has been deleted or otherwise lost, because they fail to show up in Nautilus.