From reading other people's experiences with a similar problem it seems to have been introduced with the tvOS 11.1 update and continues with tvOS 11.2. Maybe a future update will fix it.
You can also try the suggestions below.
If your TV was 4K capable I would suggest trying a newer HDMI cable. Instead I will suggest trying a different HDMI input on the TV.
Another suggestion I have is to disable a feature called HDMI-CEC. This is the feature that allows of the TV from the Siri Remote. Various TVs use their own name for the feature so you will have to figure out what they call it on your TV so you can disable it in settings on the TV
See this support article to learn how to enable/disable this feature on Apple TV.
Control your TV or receiver with your Siri Remote or Apple TV Remote - Apple Support