Wow, this is the exact issue I was encountering today with CodeShip. Not exactly following git-flow but I was hoping to merge master into release and trigger a build and deployment phase but it doesn't work.
It came from observing the amount of users claiming to have left from Bitbucket to Github within the thread. I've been following it for months but it has been active since 2013-07-17, 131 comments on it so far and it seems to be only getting more vocal.