Try these steps in µTorrent/BitTorrent to change from downloading to seeding:
1/ Stop the torrent (do NOT remove)
2/ Click with the right mouse button on the torrent in µTorrent's list and select "Advanced" > "Set Download Location…" > navigate to the file location and confirm (Save)
3/ Right mouse button click on the torrent in µTorrent's list and select "Force re-check". The torrent should check to 100% and µTorrent displaying "Finished" instead of "Stopped" in the status column.
4/ Restart the torrent, it shall go to "Seeding" or at least to "Queued seeding"
You can avoid this issue in future by downgrading to µTorrent 2.2.1 > https://www.gaytorrent.ru/details.php?id=135394