Depends on where you got the torrent, but those seeders might actually be just wrong reports by the tracker. It has happened to me as well. I’ve left torrents for months just to see if it will eventually start downloading… nope, just sitting there, idle.
Can’t say what the real reason behind this is, but my best guess is some bots are reporting wrong info via DHT and/or the trackers. Why? Have no idea, your guess is as good as mine 🤷.