Audio Description Error

I'm watching the Apple TV 'Disclaimer' .

The audio description is on permanently. On other Apple TV shows ( Drops of God / Slow Horses ) there is no audio description.

I tried voice control 'audio description off' . No luck .

I check my system settings and also check the settings for the specific show but nothing explains why one show , randomly it appears , has audio description whilst the rest of Apple TVs library do not .