I get the same thing. I’ve tried resetting Google Homes, turning off night mode, turning off IPV6, setting up the API from my wife’s account vs. mine, etc. Just doesn’t work anymore but does show status OK and shows up in history as if it worked. Stopped a couple of months back with no changes to anything on my end and hasn’t worked since.
I’ve followed every troubleshooting post in this thread and even tried another assistant package on Github. My account must be flagged or something.
Broadcasting does work fine from my Google Homes and from my phone though.