Air bubbles get trapped at the top of the master.
You have to old school bleed it from the banjo bolt.
You dont "have" to do that...I bleed brakes all the time and never bleed from banjo bolts...There are other ways to get bubbles that are stuck at the banjo loose, usually that is high point and that is what causes them to get stuck there....Simply tilt the bike sideways until its not a high point, and tap the master to loosen the bubbles and have them float up into the res