That could indicate a lot of things. It would be very difficult to distinguish a torrent from something like cloud folder sync. And that would still be a statistical guess. No ISP is going to go after customers because their VPN traffic is potentially torrent traffic.

Besides, even if they could detect that torrenting is taking place, they will not know what data is being transferred from and to where. It's a meme, but torrents are actually sometimes used for non-copyright infringing data.