I was watching Hafu's stream last night and she was coaching Trump on how to play a Miracle Rogue.
They went on a 5 game win streak from Rank 2 4 star to Rank 1 4 star and didn't get any bonus stars at all. I'm currently Rank 10 myself and still routinely get win streaks after 3 wins.
Do win streaks stop at a certain level? Are there different requirements at different ranks for win streaks?