I found the following bug. If you are in the app on Chromecast and and exit the app, the Exit Application screen pops up.
Then do the following:
1. Hit the Home button which will take you the Chromecast main screen.
2. So far so good .
3. Then re-open the HDHomeRun app.
4. The Exit the application screen is now stuck on.
5. You can't select OK or Cancel .
6. The only way i have found to get rid of it, is to Reset the Chromecast device.
Using latest firmware on HDHomerun and latest build and Android.