I have beam gen2 with surrounds etc and apple tv 4k. Up until a day or 2 ago (suspicious of the latest sonos app update from a few days ago) if i have a netflix or disney+ content that is just 5.1 and if my apple tv set to dolby atmos - i used to get on my  sonos app multichannel 5.1 and i didnt like that because the dialogue was almost always a bit more quiet like this. 
So i always went to setting and switched to dolby digital 5.1 in apple tv audio aettings and i was getting 5.1 on sonos app.

if i do the same now - i get stereo pcm. I am so confused. Am i missing something - anyone else having the same issue ?