You mean
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It doesn’t say that the MMR is bugged if that’s the post you’re referring to. That was what they said during the night after an entire day of people complaining about queues where they didn’t even get a notification about it popping and then straight to deserter, and getting loading screen into the arena but then immediately everyone getting kicked out with deserter, and similar things being reported for PvE queues as well as PvP.
Also, just to be clear, because healers can’t carry as much as a DPSer can, it means healers tend to get win rates closer to 50%. And getting win rates closer to 50%, means getting a slower climb rating-wise.
This is one of the reasons why the game’s design needs to change, move to high sustained and away from heavy burst gameplay, which places more emphasis on interrupts instead of those random burst windows where you have to throw out everything, and makes it so the healer that can fake the best can carry a decent amount.