Is it normal for Sonos users to need to go to the audio settings in Apple TV and turn on change format to Dolby Digital 5.1 in order to get 5.1 audio to a Sonos system? 

I have two Sonos setups: Amp and my own speakers, and another with Beam. I have an Apple TV 4k (latest gen) but when playing 5.1 content (netflix and plex) both systems only get stereo audio, unless I turn on change format by going to Settings > Video and Audio > Audio Format and turn on Change Format and then choose Dolby Digital 5.1 routerlogin

Just curious why this? So far I am not seeing an audio delay, which is great, but curious why I end up in stereo unless I force it, is is the Sonos system not hand routerlogin ling this or is it my Apple TV not understanding Sonos?

issue solved!!