My brand new master cylinder only seems to be cycling fluid through the rear reservoir (front brakes) when I bench bleed it. Does anyone have any ideas to get it working? I included a picture showing my bench bleeding process.

Hi All, 1/2 way through changing out my brake distribution block/proportioning valve. (Getting the booster out of the way was not fun). Just put in the block. Since it will be filled with air and I will be re-bleeding all four corners, do I even need to bother filling the master and bleeding...