Hi! I am experiencing a very strange situation with my configuration on which I hoped somebody could shed some light. I own a Sony KD-65A1 TV connected via its HDMI 3 (ARC) port to a Sony STR-DH770 receiver. Formerly, I used to own a 4th generation Apple TV which was connected to the TV directly and worked great. Last Friday I went out and bought an Apple TV 4K. Having connected it directly to the TV's HDMI port 2 (not via the receiver), it initially worked fine. However, something strange happens after both devices would enter standby for a period of roughly 30 minutes or longer: once turned back on, the TV would not be able to detect any signal from the Apple TV. The TV would be able to tell that the Apple TV is connected to it; it would also be able to specify the resolution at which the video signal is ostensibly transmitted, it would also "flicker" briefly (in what appears to be an attempt to establish connection) but no picture would appear. Both the TV and the Apple TV are updated to their respective latest software releases (TV firmware version 6.2858 and tvOS 11.3). While experimenting with this, I've made the following observations: 1. Once the problem occurs, the only way to regain connectivity under said configuration is to either power-cycle or restart (using the "Restart" option that's under the "About" menu) the TV itself. Power-cycling just the Apple TV bears no effect; 2. In some (not all) instances, the Apple TV has to be power-cycled too as it would become non-responsive to its own remote control, wouldn't "wake up", and the only way to then regain device responsiveness is to physically unplug and re-plug its power cord; 3. Changing the HDMI cable to a more expensive one had no effect; 4. Restoring both the TV and the Apple TV to their factory defaults had no effect; 5. Once the issue manifests, connecting the Apple TV (apart from instances where it wouldn't turn on) to another HDMI port (1 or 4) would work. Likewise, connecting another device to HDMI port 2 (to which the Apple TV is usually connected) works properly as well (not entirely correct, see update below). Moreover, disabling "Enhanced HDMI" mode on the TV results in regained connectivity, albeit without HDR or Dolby Vision support. At this point, the only way to regain proper connectivity under the original configuration is to power-cycle or soft-restart the TV. To me, it appears as though something in the "marriage" of the Apple TV with a particular HDMI port breaks until the TV itself is power-cycled or restarted. And then it finally dawned on me: in the Apple TV, I usually have the ability to turn on the TV with the Apple TV remote disabled ("Settings" -> "Remotes and Devices" -> "Turn On Your TV with Your Remote"). Once I re-enabled this setting, and ensured that the TV would be turned on and off via the Apple TV, the issue bizarrely disappeared. Once I turned that option back off, the issue started recurring. Still, I am not interested in having the Apple TV control my devices in this manner and prefer to have that setting off. I have seen a variety of Apple TV 4K HDMI CEC-related issues documented on these forums, some of which were fairly similar to mine, with the exception being the fact that while other posters reported that restarting the Apple TV helps, nothing short of power-cycling the TV itself works for me. It seems as though some kind of state gets corrupted, otherwise I have no way of explaining this behavior. Did anyone ever experience anything like this? Thanks in advance! UPDATE (April 28th): After digging a bit further, it appears as though this situation is somewhat more insidious than it would at first appear. Pursuant to point 2 above, when the Apple TV 4K is connected to HDMI port 2 and this issue would appear after standby, HDMI port 2 would work with other devices, given that these devices don't utilize "Enhanced HDMI" mode. Connecting an HDR-enabled device (a PlayStation 4 Pro, for instance), however, to HDMI port 2 results in a frequent, intermittent loss of signal. The only way then to regain proper function is to power-cycle the TV. I am almost confident that a hardware issue with the TV can be ruled out here, as had such been the case, functionality would not be restored upon performing a power-cycle or a soft-restart. I have a strong sense of conviction that for some reason unbeknownst, some form of "state" is presumably being corrupted such that Enhanced HDMI is knocked out until the TV is restarted.