I have used the broadcast feature for years. Particularly useful is the broadcast to a specific speaker when I need to call our child from their room. In the last week the system stopped working for specific speakers, but will do a global broadcast. For example if I say "Google, broadcast to Hunter's room" on my Android phone, I will see it recognizes what I am saying (as it spells out the voice to text), then instead of asking what the message is it replies with "Got it Pausing Hunters Room", and ultimately with there is nothing to pause.
@Jpod, thanks for reaching out and for providing detailed information on your issue. A few things: which Nest speaker is having trouble? When did your issue begin? Were there any recent changes made before the issue started? Is the Nest speaker working aside from this feature?
You can do a sequential reboot. First, unplug your Nest speaker for 30 seconds, then do the same thing to your Wi-Fi router to refresh both devices and your Wi-Fi signal. If that did not work you can remove and relink the Nest speaker then observe if it will make a difference. Check the steps below.
When you remove a device from a home in the Google Home app:
Keep me posted.