I run Savox hvs on everything and thought that was the issue and tried my hitec spare and it's the same issue.
Just did another test and it's not the MMM. Plugged a hump pack and servo into a Rx out of the Rc. Works great when I'm near. When I walk away my wife says the light(led) flickers then goes out and servos stops. As I come closer the light flickers back on. So I'm guessing the module or radio.