This is the exact same thing that is happening to me word for word. Hooked the same Apple TV 4K up in my bedroom to my pioneer vsxlx301 and it fires up Dolby Atmos as it should. Changed wires, inputs, downloaded all available firmwares/updates and the problem still persists. The receiver will show an input of 2.1 pcm on the 503 while not playing a sound while in a movie that is coded for Atmos. Non Atmos movies play sound normally. The only way to get Atmos codes movies to play now is to turn Atmos off within the atv4k menu and then it will input a 7.1 pcm signal to the 503. On the 301, all functions as intended and input shows 5.2.2 and an output of 5.2.2. Trying to decide if I should give up on this 503 and return, but limited on 9.2 in the $1k range.Hi, I just purchased a Pioneer LX503 and have been trying to get Dolby Atmos to work via ATV 4K. Unfortunately, all Dolby streams result in no sound being processed.I've checked all the settings and updated all devices, unplugged the HDMI cables, but nothing seems to work. I am able to run Atmos through the receiver from the Xbox without any problems. Has anyone been able to get Atmos to stream through the TVos12 ATV 4K on this receiver yet? If not, I'm wondering if it will require a firmware update from Pioneer to work properly.