[dlock17]

It would be cool if this was true, but no, Stremio does not seed cached files.

https://github.com/Stremio/stremio-features/issues/626

Somebody made an extension that adds cached torrents to your local qbittorrent instance though, which is a nice alternative.

https://github.com/Vance-ng-vn/Stremio-Seeds

Note: I haven't used this, since I use Stremio from a Chromecast.