What exactly is your source? What media device are you using?

Disney plus on a Sony A90j. Was receiving atmos signal on the s2 app until I added the rear speakers. Sounds great but it’s saying I’m receiving 5.1 now

It’s a Disney+ problem. It is just a coincidence that it started to happen when you added the surround speakers. Test another app like Netflix or HBO Max and Dolby Atmos should still work.

Read more here:

https://9to5google.com/2022/07/21/disney-plus-dolby-atmos-android-tv/

Brilliant. Thanks for your help, it’s been driving me mad trying to work out why today