It seems odd to me that another app was the culprit for me. The HDHomeRun app doesn’t even have to be running - just installed. I can duplicate the issue on my setup 100% so I’m confident there’s a conflict between the Ring app and the HDHomeRun app.
For the time being I am installing and uninstalling the HDHomeRun app as-needed.
It’s a pain to uninstall apps, but I suspect you’ll find the culprit on your setup by uninstalling each app one-by-one. Try to show your Ring camera and if it doesn’t work just reinstall the app and move on to the next one.