Hi!
I noticed an annoying ktorrent 3.1.2 bug. I'm on ArchLinux, with KDE 4.1 and Ktorrent from official repositories.
Sometimes when a download finishes, Ktorrent shows the notification window and then it quits, but the notification window stay stuck on the desktop, on top of all other windows.
I can't tell you if ktorrent crashes, because there's no crash dialog and when I restart it, nothing happens that could let me think of a crash.
I'm not sure about the type of torrents that trigger this bug, but I noticed that this behavior happened with one file torrent (a torrent with only one file in it).
It happened with this just this morning: http://www.gameupdates.org/details.php?id=383.

This is caused by a behavioral change in Qt 4.4 (which in my opinion is a bug), we have fixed this. There have been several more reports of bugs like this.

The fix will be part of 3.1.3