What determines whether or not Channel Surfing works? I have it enabled on four AppleTV's and it's working on three of them, but not the 4th one, the primary one, which is a 2nd generation 4K model. It's running the current tvOS 18.5.
Edit to add, this was SOLVED - by toggling "Channel Surfing" off and then on again in Settings → Playback → Remote Control.