blankfor101,
Thank you for your suggestion.
Yes, I did trying deleting both the app and its data. That did not appear to have any impact upon playing of OTA live TV.
When Plex for Apple TV 8.7 was released, I manually deleted both the app and all its data, but still can’t play any OTA live TV from our HDHomeRun tuner, and playing recorded HD shows is still problematic. (The Apple TV HDHomeRun app has never had any such difficulty, nor did Plex for Apple TV app versions prior to version 8.6. My wife did recall a few occasions of problems playing a OTA live TV show that was being recorded.)
