Leo, Thanks for uploading 4.0.1-1. Good idea to disable libtransmission-dev for now.
I did a bit of testing, and it seems to get a bunch of those old "no bencoded data to parse" errors, and a whole bunch of fully downloaded torrents showed up as 0%. So I cherry-picked to the tip of upstream/main (as of yesterday) above your branch, see branch cherry-pick-devel on https://salsa.debian.org/bap/transmission, and that fixed *everything*! All fully-downloaded torrents verify completely and show as 100% downloaded. Yes, even all the single-file ones. And no more "no bencoded data to parse" errors. If you look at the commits, there are a bunch of seemingly-relevant bug fixes. And also some minor stuff. Anyway, I think it would be a service to our users to not have them upgrade and suddenly half their complete torrents show up as 0% and they're getting screenfulls of "bencoded" errors about torrents that used to work fine. So I think it might be a good idea to upload a version patched with these upstream fixes, or at least some coherent subset of them. Really upstream should release 4.0.2 with these fixes right away, since 4.0.1 is, technically speaking, what we in the biz call "broken". But I digress. Cheers, --Barak.