When the lock screen or control center on my iPhone shows content playing on my Apple TV, the volume slider is grayed out. I also can’t control volume using the volume rocker while the Apple TV Remote app is open. I have a simple setup: just an Apple TV and a Samsung TV connected by an HDMI cable. HDMI-CEC is enabled and Volume Control is set to “Auto via HDMI” on Apple TV. HDMI-CEC is working for other functions, including turning on/off the Samsung TV when I wake/sleep Apple TV, so not sure why volume control isn’t working. Am I missing something?