I have a client with an LG soundbar on a Samsung TV. We got rid of using the Samsung volume commands by using one of the LG command sets on the DirecTV remote! The Samsung volume has to be up some, but no Samsung command is ever sent, so the volume notification never appears.
Maybe you just have to let it keep appearing, but if I were the customer I would call that a failed installation. It just shouldn't be that way.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw