Completed torrents incomplete

  • Recently after several torrents finished downloading and as they sat there seeding i noticed they were incomplete as in the torrent size(Torrent size 2.48GB) and the Downloaded size (Downloaded size 1.91GB) did not match but ABC will not download the last little bits and the files will not work without those last bits of data

    How do i get the ABC to realize that there is still more to download without having to redownload the entire torrent