Having issues with ATV 4K! Dolby Atmos not working with streaming apps. Coming thru as PCM. Why?!

Hello Apple Support Community! 

Ok, so I have Apple TV 4K (HDMI cable) directly connected to my Denon AVR x1600h receiver; then to my LG TV (via HDMI). Prefer not to use sound through my TV, which is why I'm not going through my TV first. Also, my speaker setup is 7.1. 

So I bought my ATV 4K last week (10/13/2022); followed the setup instructions; and out of the box everything worked great! Dolby Atmos (when available) was successfully displaying and playing thru my Denon receiver.  I was able to get Atmos quality sound thru all my streaming apps (Netflix, Disney+, HBO Max, AppleTV).  Then, a couple days later I noticed there was an update available for Apple TV so I updated...and that's when everything went to ****! After the update, I went to watch one of my shows on Disney+ (yes, broadcasting in Dolby Atmos) and to my surprise Atmos wasn't working anymore. Instead, it was playing and displaying on my Denon as "Multi In Stereo -

PCM 5.1."  What's even more strange, PCM is only coming up when I play other streaming

apps.  But, when I stream Apple TV content...Dolby Atmos displays and plays on my receiver perfectly!   

Based on what I've read in this forum, it looks like ATV 4K is still having issues. I've been trying to fix this for days now, but I'm out of ideas.

Here are the settings I've tried so far:

Denon X1600H settings:

HDMI Audio Output is set to AVR (not TV); which is correct because ATV 4K is directly connected to the AVR. HDMI Passthrough is turned ON. This allows HDMI signals to transmit through Denon's HDMI Output when in standby power mode. HDMI Control function is turned ON. This allows ATV's remote control to control Denon's volume and power on/off settings. The ARC setting on the HDMI Monitor Connector defaults to OFF; which is correct because I don't want to receive sound from the TV via HDMI.  TV Audio Switching defaults to ON.  Not sure if this should

be OFF.  When ON it allows automatic switching to the “TV Audio” input when a TV connected via HDMI sends an appropriate CEC control command to this unit.

Apple TV 4K settings:

Audio Output is set to Auto. Audio is set to Receiver speakers. There's another Audio setting set to Auto.  I forget what it's called, but I can change it to 16 Bit. Dolby Atmos is ON. And, ATV 4K is enabled to control the Denon's volume and on/off power control.

Before jumping on this forum, I even did a full factory reset on both the Denon

receiver and ATV 4k, but that didn't work either.

In conclusion, I think my ATV 4K is decoding the audio format for all my other streaming services instead of allowing my receiver to decode it. That's probably why I’m still seeing it play in “Multi In Stereo – PCM.” Since ATV's content is working with Dolby Atmos, it makes one wonder if they did this on purpose with the other streaming apps?!  Anyway, if Apple is doing the decoding, is there a way to turn that off? If there is a fix, please provide detailed guidance one what my settings should be between ATV 4K and receiver.