I just got a Heroic Victory which dropped me from rank 17 to rank 810. Possibly to do with my opponent conceding rather than playing it to the end? In any case, I've had this happen to me once before, but this time I thought I'd make sure to post while I still had the replay. Replay attached.
I'm not super fussed about my ranking - getting it back gives me something to work towards - but since the alt-f4 punishment scheme has come in I do mind that people might think a sudden fall in ranking means I'm a dirty drop hacker. Please fix!
This was with v1.6.0
Get on, Kroq-Gar, we're going shopping