I have the same issue. I'm able to program the XR15 remote to my LG TV with no problem. It will turn on and off and control the volume. Then, I program the remote to my Sony soundbar. It programs to thee soundbar with no problems. However, once I program the remote to thee soundbar, it will no longer work to turn the TV on or off.
The weird thing is that the remote will still let me choose different inputs on the TV when I press the "TV Input" button. That makes me think that it is programmed to the TV and is able to partially control it. But, for some reason it will not turn the TV on or off after I program it to the soundbar.
Any help is appreciated. Thanks!