Just upgraded to tvOS 12.1.1 on Friday Dec 7, 2018. Have received 2 "connection lost" messages on channels I normally have no challenges with. I have recently made a slight change with my amplification (pre-Amp to Amp only), but the signal strength is still showing very strong for these channels. Wondering if there are any changes with how ChannelsDVR app works or something else with 12.1.1 that make it different ? I remember reading somewhere that Channels app doesn't use the normal Apple APIs / functions for video display. For example if you turn on the Developer mode feature that displays network /framerate / etc, it shows in many other apps but not in Channels. I believe this has to do with efficiency and other features. Anyway this is mostly just a post to see if any others see changes since tvOS12.1.1. Also I watched Thu Night Football last night for hours with no "connection lost" messages. The 2 channels I experienced error on today were different channels, but still unusual as I normally never have issues with stability. I also want to note that using Channels iOS apps at the same time on some of the same channels was not getting "connection lost" like the Apple TV app was. A little early to call this officially some type of problem, could just be anomalies with my setup, network, etc. I am running AppleTV wired though.
I’d guess maybe something with connectivity if your appleTV. Is it WiFi or Ethernet? I have seen no issues since upgrading to 12.1.1
ATV is wired ethernet less than 10 feet from HDHomeRun. Things have been more stable lately and I can experience many hours of playback without an error. Something still seems less stable and it may just be the changes in my antenna / amp / pre-amp setup that has caused more issues for me than normal. I have used 2 different channel master pre-amps and a regular amp over the past couple weeks. My HDHomeRun doesn't like something from the new CM units for some reason. Anyway I think it was just a coincidence that I started noticing dropouts around the same time of the iOS update. I do believe the AppleTV app is a little more likely to drop to a black screen with "Connection Lost" message than the iOS playback apps for some reason. Based on limited personal experience with signal hiccups from my antenna feed.