A few users reported that Transmission stops working for no apparent reason on the latest firmware. (Andimaginary) The possible cause is that Buffalo changed around some of its libraries in the latest firmware and I had to complie the transmission client from scratch for this. It’s possible that the libraries I built it with are not exactly the same version that Buffalo uses and this causes issues.
I’ll try to recompile transmission with the same libraries Buffalo use but I need some time to do it. Until then the workaround is to reset your transmission config files and downloads to default state (remove/rename your settings.json, remove some of your torrent files) and generally play around with the transmission settings and files. For example check if you have any trackers with HTTPS or any SSL encrypted connections, see if a specific torrent crashes it or maybe the number of torrent files. You can also revert to the built-in torrent client. (with limited functionality)
I need the feedback on your tinkering because I was not able to recreate the issue (transmission didn’t quit on me) and so far none of the remote debugging yielded any results.