appletv resets remote's volume control to auto(off)

i have the appletv 4th gen connected to a surround sound system. once in a while (after it goes to screen saver, or it's been a few hours, or just randomly), the appletv defaults the remote's control from the surround sound to "auto(off)". which means that i can't control the volume until i go into settings and switch it back. this seems to have just been happening since the latest update (i'm on 17.1).