I already opened a bug on ktorrent, saying its fixed upstream but apparently no one took care to propagate downstream to debian version.
When I realized the bug was in libktorrent and still unfixed, I installed transmission-qt that works but I dislike it.
Today I took the plunge, motivated but kde6 transition, and tried to see if version 24.08 works. It does work and is easy to compile/install (you also need libktorrent 24.08). I installed it to /usr/local and removed official KDE5 Debian one (well except the libtorrent library that is also using by kget).
If someone with KDE6 packaging knowledge can make a .deb version I would appreciate it. I know the focus is not yet on extra packages but still torrent is a good way to share isos.
Regards and thanks again for KDE6. -- eric