This issue is back, and causing enormous bandwidth loss to leeching. In a nutshell, some downloaders have figured out how to "ghost" themselves as IPv6 and IPv4 couplets, one of which DLs at maximum velocity while the other reports reception to uTorrent, fooling the application into believing it's dealing with disparate peers who are sharing nicely. The result is that uTorrent continues to reward them with pieces far in excess of their actual sharing. This is intensely frustrating as an uploader of huge torrents in initial-seeding mode in which, to manage my bandwidth, I halt uploading after the Availability of the torrent exceeds 2.0. -- In the old days before IPv6, this normally wouldn't happen until several peers were "99%"ers (meaning Avilabiliy would quickly shoot to 4 and higher as the 99%ers quickly traded the last rare pieces); now, Availability might reach 2.0 when the highest percentage peer is no better than 85% (well, him and his ghost buddy), with the next ghost-pair many percentage points farther down. If a ghost-pair is a leech who splits soon after hitting 100%, they could up robbing 5%-10% of the torrent (and, if several couplets are leeches, it can be a lot more than that) -- a possibility that initial seeding mode exists as a feature to explicitly prevent. During initial seeding, non-ghosted peers are almost completely shut out of any meaningful fraction of my upload bandwidth (since they don't have a ghost partner instantaneously reporting successful re-trades), as uTorrent will upload virtually exclusively to ghost-pairs. I can only cross my fingers and hope that not too many of the ghost-pairs are leeches who'll disconnect at 100% before they've shared their rarest pieces. To give you some idea of bandwidth loss potential, I was recently "robbed" of over 40gigs out of a 250+ gig torrent established via initial-seeding, despite there being nearly a hundred peers in it near the finish. This occurred even though I had posted the torrent with a smaller piece size of only 4mb -- if I had gone with the default of 16mb or higher, the loss-to-leeching would have been even more severe.
