At random times when I turn on my TV using either the Chromecast remote or my dedicated Toshiba remote, the television displays a black screen and neither remote will affect the television. I have to manually unplug and re-plug the dongle into the HDMI port on the back of the tv to restore functionality to both remotes.
This is random behavior (not every time, but almost half the time) and began about a month ago, after an update.
Restarting the device does nothing. A physical disconnect and reconnect is the only way to instantly restore control of my set to normal operations. The dongle is only a couple years old and worked flawlessly until just a few weeks ago. I do not use an android device to control anything. Just the remote.
I'm sorry for the delayed response. Could you please plug in the Chromecast with Google TV (4K) into a different HDMI port on your TV? Also, if one is available, plug in your device into a different TV screen and observe its behavior.
If the issue persists, perform a factory reset on your device. Here's a guide: How to factory reset your Chromecast.
Keep me posted.