Apple TV 4K remote stopped controlling audio via Apple TV--now controlling through TV instead

Apple TV 4K remote stopped controlling audio through Apple TV. My system uses two Home Pod speakers and up until today the volume button on the Apple TV remote controlled the volume of the pods. Now it shows that it is controlling volume on the TV, but it does not actually change the volume! The bar on the TV (for the TV's sound, not the Apple TV bar) goes up and down but the sound does not change. I made sure that the Home Pods were set as the audio output and the TV was not, but the problem remains. I reset the remote and that did not help. I can't change the audio source because I'm using Home Pods and they aren't HDMI connected. Help?