Surround sound (5.1 ch) broken except Apple TV app on Apple TV Box
I've spoken to an Apple tech, but we couldn't find a solution. After the latest update, I noticed that Netflix, Disney+, Stan, and Prime Video no longer deliver surround sound (5.1ch). Interestingly, the Apple TV app plays surround sound without any issues. I also tested all my apps (as above) on LG TV, and all of them play 5.1ch sound perfectly. I also tried changing the "Audio Format" to 5.1ch on my Apple TV, but that didn't work either. Since the Apple TV app on my Apple TV Box produces surround sound and the other apps don't, I wonder if there's an issue with the latest update. Has anyone else experienced similar issues?
Apple TV 4K, tvOS 18