Albert Holler

I am having exact same problem. Here is my camera info and senior happening. Using 2 Yongnuo Speed Lights YN 560 IV and controller YN 560 TX on Olympus E-M5 II. In settings on the camera I have RC flash mode turned off. Both flashes set at RX in manual mode on channel 1 One flash is set at A Group the other is set at B Group I can control both flashes with controller changing power of flashes and can set the zoom on each flash. also able to turn off C, D and E group. Using the test button on the controller both flashes go off. Tested this three times in a row and both flashes go off all three times with test button. Now here is my dilemma! I turn on the camera and try with the shutter button and both flashes go off the first shutter release. But the second push of the shutter button only A group works and not B group. B group will not work again until I change groups with the GR button on the controller and then both will go off once butt the next shutter release only A group works. In one of the above comments they mentioned that if they adjusted the power output it would reset it and both flashes go off again. Yes that works with mine also. Also if you adjust the zoom it will reset it both will go off on the second shutter release. Would really like to know what's going on. Its pretty annoying.