Apparently Google rolled out an update for the Nest Hub a week ago that contained a bug.
Previously, I could listen to the radio on big Speakers via the Nest Hub ("Play [Station] on [ChromecastDeviceName]") or also set the Chromecast as the standard for outputting music.
Since the update this no longer works. No stream is started. I can still have the radio start locally on the Nest Hub and then redirect it to the Chromecast via touch. But any attempt to direct the music to the Chromecast via voice command (or to set the Chromecast as default) fails.
Google, please quickly provide an update that fixes the bug and brings back this essential feature.
Radio is streamed from TuneIn in Germany if that matters.
