On Audio/subtitle section of TV client :
Adding language to the right (Preferred languages), when closing configuration, theses language was keep on left side (Available languages).
That mean that we can add same language over and over

h4. Steps to Reproduce
Open Configuration.
Go to TV Client section.
Add language in "Preferred languages" for audio and/or subtitle
Close configuration.
Open Configuration.
We can again add the same language.

h4. Additional Information
We need to analyse language list and remove already added language in "Preferred languages" section