Abnormal matchmaking behavior in ranked - was there a change to how it works?

I play regularly almost every evening and have pretty consistent win rate around 51% in silver league. Two days ago Heroes of the Storm had some sort of service issues where the game would show error messages when trying to start a match or not launch at all. That went away after a couple hours, but after that I lost 9 out of 10 ranked matches. The players I was matched with were beyond bad, I pretty much haven’t seen such poor play in the 8 years I play the game. I was perplexed and discussed it with several other players who said that they also see unusually terrible players in last day or two.
Was there some sort of unlisted change to how matchmaking works? I don’t see what else could cause this sort of difference from one day to another. Ranked matchmaking was working rather poorly before, but this does it for me - I don’t think I will be playing HotS anymore.