I’ve looked this up and even people with the best connection have been encountering this problem, and it has been occurring for over 3 years now, because that’s how far back I’ve found posts talking about this problem. I’ve experienced on many different occasions of disconnecting RIGHT as the game ends, even after winning, only to be disconnected, and for it to be counted as a loss, and get a “leaver” status.
I’ve seen Blizzard reply to these claims only asking what the specs and internet provider are with the people and telling them to ‘check the support page’ if they’re still encountering problems, of COURSE they’re encountering problems, because A LOT of people have been discussing it and they won’t look into it! I don’t have the best internet but I can a play through a WHOLE game without disconnecting or lag only to be dropped from a game at the VERY end after winning.
One post claimed that the problem was when someone played Garrosh, and my last game included a Garrosh and I happened to disconnect at the very end. I don’t know what Blizzard is doing but they really need to hear the players more. Like for real. If people are still talking about this after 3 years something needs to be done. ignoring something won’t fix it.