Google and or Spotify haven’t  implemented it properly for the Sonos system?

When you speak a Google Assistant command, all Sonos does is forward that to the Google cloud, and then deals with what is sent back. 
 

When Spotify is accessed, again Sonos receives a command to go to Spotify’s servers and play whatever stream is handed to them. 
 

Sonos isn’t making any decisions in this process, it’s somewhere between Google and Spotify. 

I don’t know who marked that as “Best Answer” because it’s not even an acceptable answer of any sort.

I’m not speaking through Sonos, so Sonos is not sending anything to the Google Cloud. I’m speaking to a Google Home Mini. I’m sending the exact same command to GA with the only modification of “on sonos speaker X”

i.e.

“Shuffle playlist A” = GA plays playlist A in shuffle mode, no problem. Per your logic example, GA is requesting the Spotify service to play shuffled, the first song that is played is random from the playlist, and plays on the Google Home Mini speaker. The next song played is in shuffle order as expected, and so on.

I can issue this same command on my phone, and it also works. 

I can issue this same command in my car, and it also works.

“Shuffle playlist A on <Sonos speaker X>” = GA should be making the same request to Spotify, and just routing the playback to over to Sonos speaker X… except Sonos speaker X plays it in sequential order without shuffle.

I have a hard time believing the fault is on either Google or Spotify in this use case, when it can be demonstrated the core “shuffle playlist” command behaves as expected if Sonos is removed from the equation and other output devices are handling it correctly.

I also know Sonos can handle the concept of a shuffled Spotify playlist because I can manually select and shuffle one. Or alternatively I can start a Spotify play session on my phone and cast it to my Sonos. Both of which shuffle as expected.

@RyanS_1,

Only basic voice commands are supported, as outlined here in Google’s support pages…

https://support.google.com/assistant/answer/7539710

It does mention that some commands are not supported on all assistant ‘enabled’ devices. It appears that it is very much down to Google themselves as to what syntax they allow customers to use on Sonos. It’s clearly a limited subset, probably so that their own nest devices remain competitive, in the same/similar way that not every Amazon Alexa syntax is available on Sonos.

As one of their customers, it might pay you to canvass Google to allow further voice instructions?

In my own use-case, I started out with Google, but later switched to Alexa instead, as that in turn allows Sonos voice control (SVC) to also work alongside, expanding the available voice instructions, but sadly the Google Assistant only installs/works ‘standalone’ on Sonos at the moment… let’s hope that Google will change their policy on that aspect too and allow their assistant to work alongside others. 

As @Ken_Griffiths says it seems Google chooses to command Nest speakers differently (often in a more consistent way) compared to other non-Google speakers. My Nest Mini that is coupled with an IKEA Symfonisk speaker acknowledges commands with a civilized sound, while GA via Sonos always gets me a spoken acknowledgment. There’s also other differences, like the very nagging fact that GA via Sonos often does not get me my the right radio station on Sonos. The fact you only seem to be able to shuffle Spotify playlists by voice when you use a Sonos speaker that is set up to be a designated speaker for a Nest Mini could be such a difference too.

So you’ve  also noticed different behavior between different devices. It could be this is because  GA sees the Sonos speaker that is set up to be the designated speaker for a Nest Mini as more of a Google speaker, while other Sonos speakers, even when commanded through the Nest Mini but not having the same direct relationship with it, are seen as “GA via Sonos” speakers and seem to be given less features than “GA via Google” speakers.

This difference is feature sets does look like it is a Google choice.