Strange Problem with HDMI Control

[PTVMan]

I have a new LG OLED TV that has apps like Netflix, Amazon Prime and Hulu that I want to use to watch series available in 4K HDR (c'mon Apple!). To get audio from the apps I have the TV connected to my Marantz receiver via HDMI (ARC) so whenever I open an app like Netflix the audio switches on my receiver to TV Audio. It works great. However, upon exiting the app my receiver immediately goes to the input for Apple TV and not back to my cable TV input. I've tried turning OFF Home Theater Control in Apple TV settings, but that does not solve the issue. I know this is complicated, but is this a problem with my Apple TV or with my Marantz receiver?

 

[waw74]

HDMI-CEC can be a little flakey when using multiple manufacturers

I'm guessing it's in the TV, since it's when you quit the app.
although the aTV occasionally gets a bit grabby, and takes control back when you don't want it to.

maybe try swapping the HDMI cables for the AppleTV & cable box. In case there is a default port that it goes back to.
if you're watching cable when you start netflix, it still goes back to the appleTV?