Hi @jassodhi123, welcome to the Sonos Community!
I’m sorry to hear you’re having trouble locating this playlist. In the Sonos app, the playlist name should be next to the artist name. If it doesn’t show then I’d recommend restarting the app by closing it and re-opening it. Currently we’re aware of an issue where music started in the Sonos app doesn’t populate Apple Music’s recently played, but we don’t have an ETA on when this will be resolved.
If you started the playlist from the Sonos app but don’t remember the name, then I would say it’s lost as you wont be able to save or find it from the now playing screen. It’s also possible this was the ‘autoplay similar songs’ option that some music services offer; Apple Music and Spotify has this feature. If that’s the case, then there wouldn’t be a playlist to save.
Using Airplay will stop this from occurring as that will save songs to your Apple Music recently played as expected. I’d recommend using that as a workaround for now.
I hope this information helps!