A new season of heroes league started yesterday, but the players have already started to complaint on the bad pick and discharging of their mmr. Players of Master league managed to get to the Platinum or Diamond league, but that should not happen. Blizzard reacted to the complaints almost immediately. Here is a quote from the official forum:
“With yesterday’s patch, a number of players unfortunately encountered an issue that caused them to be placed at ranks that were significantly different from where they ended the previous season. This issue is unrelated to our Performance-Based Matchmaking implementation, and is instead a result of an issue with Matchmaking Rating seeding from the previous season. We’ve finished diagnosing the problem and are currently working on a fix which, once completed, means that we will be resetting the Hero and Team League records (including placement matches) of any affected accounts.
In order to implement the fix without taking down the servers, we will need to disable the Hero and Team League Matchmaking queues for roughly an hour. Our current plan is to start this in all regions at some point tomorrow, Dec 14, but we will keep this thread updated if anything changes. For players that have yet to complete your ranked placement matches, we recommend waiting until this issue is addressed.
We sincerely apologize for the inconvenience that this causes for those of you that have already made significant progress into Season 1 2018. We’re extremely excited to show off the major gameplay changes included in this patch, and will be working hard to implement a fix so you can experience everything the Nexus has to offer without major issues like this. Thank you very much for your patience.”