Just the same happened to me. In spite of several attempts it kept leaking. New silicone, new rubber band inside the rim - you name it - did not help. We even detected the very spoke that was reponsible for the leak, but to no avail. So I ended up putting a tube into the tyre, problem solved. Now I run on three tubeless tyres, and the fourth with a tube. I would have preferred tubeless all around, but I can live with this. As for handling and comfort, I do not notice any difference.
