A connection diagram/description would help.
Why wouldn't the dialog sound also come from the Denon Receiver?
Where did you expect the dialog sound to come from?
What is the MWDA HDMI connector actually plugged into?
Have you tried it without the Denon Receiver?
Have you tried other content?
1. Somethng other than Netflix,
2. Different content on Netflix.
3 locally stored content
Carnac the Magnificent thinks it's a possible DRM issue but what does a dead telepathic comedian know anyway and how did those questions get into a mayonnaise jar? Well he is telepathic...