I just got a TCL R625 which I am using with a Sonos Beam (Hooked up via Arc HDMI) and two Sonos Play 1s. The Roku software is updated to 9.2.2 build 6106-88. I can get surround from every TV app (Amazon, Disney, Apple TV, Vudu) except for Netflix which appears to be playing back in stereo? The TV is set to autodetect the audio source but I have tried auto passthrough, dolby digital etc and no change.
What is odd is I have this exact Sonos surround setup on the older TCL R615 and it plays surround in Netflix just fine.
Every device is up to date (Sonos even says Dolby 5.1 signal while the Netflix stream is playing). I have noticed the surround going to my xbox seems to work off and on as well which is odd. It also shows Dolby 5.1 in the sonos app while playing.