Same issue. I'm able to configure zsnes to exit by pressing the right joy stick on my Bluetooth Xbox one controller, though.
In LB, I can clear and readd the button 7+8 combo, but after launching any game through any emulator, the assigned combo fails.
I'm using latest moonlight to stream to windows 10, latest LB premium (and beta), drivers, emulators (zsnes, pcx2, retroarch and it's cores, etc) with a bluetooth Xbox one controller. Due to stream performance issues, opted to connect same controller with USB via usb hub to Android TV box.