There is an interesting comment in this video. Blizzard said that NetEase has a fix. It is a little after 4:45.
Does that mean NetEase is in charge/ responsible for the coding rather than Blizzard?
Not necessarily. The game was co-developed and both companies have large teams of developers. Here’s a direct quote from senior game producer Joe Hsu. When asked what each company was working on for the game, Hsu responded:
‘It’s really a co-development. There’s no clear divide — you do this; we do that. From both sides, we can come up with ideas and work on implementation. It feels like one team, even though we’re not physically together all the time. It’s a very good partnership, where we’re all in it together.’
This quote would seem to suggest that NetEase is at least responsible for the matchmaking system.