Hey Neal,
You are going to need to bleed the master. it probably has an airlock between the m/c and the block. The prop valve wont switch back until it senses brake pressure on the rear. Sometimes they will switch back if you bleed the opposite end(front in your case), you may even have to loosen the front bleeder and pump the brakes a couple times with it open. then start fromscratch bleeding.
Good Luck
John