Hallo @idlewise and @cwasmund
OK, here is what you can do to permanently switch off the NAR:
Step 1:
On the remote control press on the Menu button
\=> Tool Box
\=> Advanced Settings
\=> Audio Settings
\=> turn on "Dolby Digital
Step 2:
On the remote control press on the Menu button
\=> Tool Box
\=> Preferences
\=> Soundtrack Language English
To ensure the settings are memorized by the Horizon Box, please put the box for a few minutes in standby mode. Then the NAR should be gone.
Hope you will finde this information helpful!
Best regards,
Frida