Thus far after doing the factory data reset on the NVIDIA Shield TV Pro’s and installing the Tablo app to get audio working, audio continues to work as expected, even after installing and configuring all the other apps.
On the Chromecast with Google TV, I do hear the navigation clicks (e.g., when I do a rapid scroll through the list of recordings), so that part of Tablo audio does come through. It’s just the audio from live or recorded content that doesn’t come through.
I neglected to mention that the TV we use for the Tablo HDMI connection is a Sony with Google TV. So I can play the Tablo content on the Sony TV either by switching to the HDMI port for the Tablo or running the Tablo Android app on the Sony TV. Both work fine. On the Sony system I have not had to do a factory data reset to get audio to work through the Tablo app.