For the static feedback you just need to go into your S Voice app and turn off always listening. And as far as the actual Google Assistant being unresponsive or suddenly going stupid, there is a YouTube video on where you need to clear out your cache in the Google app in your phone settings not on Google assistant app, in addition to your history that it has saved up as you've been using the Google home. In addition to cleaning out the stuff that the YouTube video will tell you, I also every other time just for good measure go in to the boot logger on Startup and clear out my cache partition on my phone just in case anything resides in there. And like in the video says you might have to set up your hey Google Ok Google trigger