When "unlock" doesn't work, I can push button 100 times, it still doesn't unlock. I attached a bulb to wires going to lock actuator to check voltage and when "unlock" doesn't work there is no voltage coming to RF actuator. That means master switch or BCM are the problem, not actuators. Most likely BCM, because door lock actuator works all the time.
I still bought new master switch from ebay just in case ($19 shipped) and probably get BCM from junk yard if unlock stops working again. Does used BCM need reprogramming?