Welcome Jonathan Giles,
Thanks for reaching out to Microsoft Q&A Forum. I understand the audio in Movies & TV keeps cutting out and coming back on all of your Xbox consoles since a recent update, and reinstalling the app didn't help.
To narrow this down, could you share:
- Does the sound drop at regular intervals, such as every few seconds, or at random times?
- Are you streaming the titles, or playing content you have downloaded to the console?
In the meantime, you can try these steps:
1, Switch the audio output to uncompressed stereo
- Press the Xbox button, then go to Profile & system > Settings > General > Volume & audio output.
- Set HDMI audio to Stereo uncompressed.
- Set Bitstream format to None, and turn off Dolby Atmos for home theater or Windows Sonic if either is on.
2, Turn off automatic display mode switching
- Go to Settings > General > TV & display options > Video modes.
- Uncheck Allow 24 Hz, Allow variable refresh rate, and Allow auto low-latency mode.
3, Turn off HDMI-CEC
- Go to Settings > General > TV & display options > Device control.
- Uncheck Allow HDMI-CEC, then test playback again.
4, Do a full power cycle
- Hold the Xbox button on the front of the console for about 10 seconds until it shuts down.
- Unplug the console, and the TV or soundbar if used, for 2 minutes, then plug everything back in and turn it on.
5, Make sure the console and app are up to date
- Go to Settings > System > Updates and install any available console update.
- Go to My games & apps > Manage > Updates and update Movies & TV if an update is listed.
Looking forward to your update.