Deluge
I've just very recently installed Arch & deluge seemed to be working fine. My previous linux install was slackware based and that's still working fine too. But after syncing in pacman to update the system my copy of deluge was upgraded to Deluge 0.9.09 & now all my torrents are trackerless.
They don't report to anything, I have no incoming connections and when I click Edit Tracker on a torrent the field is blank. If I try to add a tracker manually the whole list of torrents disappears until I next start Deluge. It's very odd.
Edit:-
Have upgraded to deluge-1.0.0-1 & still get the same problem. Seems the only solution that works is to remove the torrents from Deluge and then reopen the torrent & let it check the data through to 100%. That seems to make the tracker show itself again