It seems I’m having a situation with my Apple TV 4K. If I play any source in Dolby Vision for example Mandalorian through the Apple TV (Disney+), the TV will show it as an HDR signal. But when I play the same source directly through the Disney+ app on the TV (Google TV), it shows up as Dolby Vision. I also noticed that on the Apple TV under Format I do not see any Dolby settings, only HDR and SDR. The TV is a Philips 75OLED808 connected via eARC to a Samsung soundbar. I would appreciate any tips, thanks!
My Sony Bravia was doing the exact same thing for about 2 weeks when I first got it. All of a sudden the ATV started working properly with it, doing the exact same thing you are talking about. Not sure.
Think about doing a reinstall of the Apple TV tonight.