This issue of not being able to broadcast to a specific device is a
different issue than the one reported at the top of this thread. The
ability to broadcast to all devices with a single voice command was
broken but is now fixed.
Broadcast has also stopped working for me within the last day or two.
Your trick of saying "Broadcast" and then waiting for the prompt does
work, but this doesn't help me because I'm using the Google Assistant
SDK from Home Assistant to make announce...