Normal, not a fault. When audio routes through the TV, each app is on its own, and three things must cooperate per app before surround reaches your AVR.
First, the app itself must output multichannel audio on your TV's platform. Apps differ on the same TV: one streaming service sends Dolby Digital Plus, another sends stereo PCM on the same television because that app version was never updated for that platform. Nothing in your system can add channels the app never sent.
Second, the TV must pass the format through unchanged over ARC or eARC rather than downmixing it to stereo. Look in the TV's audio output settings for pass-through, auto or bitstream. Many TVs ship set to PCM, which quietly folds everything to two channels while displaying no error at all. Your AVR then shows PCM 2.0 and gets blamed for it.
Third, the link must have the bandwidth. Compressed formats such as Dolby Digital and Dolby Digital Plus travel over standard ARC. Lossless formats, Dolby TrueHD and Atmos in its full form, need eARC on both TV and AVR, with a cable that supports it. If your TV or AVR predates eARC, lossless will never pass, whatever the app sends.
The bypass that ends this argument permanently: plug your main streaming device directly into the AVR and let the AVR feed the TV. The AVR then receives whatever the source outputs, with no TV in the middle making decisions on your behalf. This is how we wire every installation where the client cares about surround, and it removes an entire category of support calls.
Where does the rule stop mattering? If your only sources are the TV's built-in apps and you cannot add an external streamer, you are living inside the TV's audio output menu. In that case send us the TV and AVR models and I will find the right output settings for that specific pair. It is usually one menu item, and it is never the one you would guess.
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