Note that if you have been part of a file sharing network recently, there will still be aa bunch of computers trying to connect to your PC requesting the file(s) you were sharing. sounds like that's the case here, where you have a long trickle effect of PC's asking for the file. You don't have the torrent app open so there is no actual upload happening, but the *requests* will continue to come in for a long time. so... Most likely it's fairly harmless.