

The qbit logs just say “torrent removed” without further explanation
So the logs don’t have the torrent finished line right? e.g. It never logs "Torrent download finished. Torrent: “YOUR-TORRENT-NAME” ?
If so my guess is what the other commenter mentioned, try changing the settings not to remove the torrent & see how it goes.
Agreed, I always leave everything seeding and also disable queuing. Leaving “Global maximum number of connections” at default setting (can be set lower) along with configuring Global Rate Limits Upload/Download to something appropriate works perfectly.
Torrent clients are smart enough to juggle the active torrents and share the allowed bandwidth between them without you having to micro-manage the whole thing.