Hi Scruffytinker,
If this only happens with one specific title but other titles in the TV app play, we'd recommend restarting your device you're watching on.
If the problem persist, then reset the TV app using these steps:
"If you’re having problems and the Apple TV app still doesn’t respond after restarting, try resetting the Apple TV app. When you reset the Apple TV app, all data is erased, including your accounts and configuration.
- In the Apple TV app
, navigate to Settings. - Go to Reset, then select Reset.
- Resetting the Apple TV app restores it to original settings and removes your personal information, TV shows, and movies from the smart TV."
Should the issue persist, contact Apple Support to take a closer look.
Take care.