A4 Mk1: Keyboard White Keys not working anymore

Hello from France fellow Elektronauts,

What is wrong:

My trustworthy A4 Mk1 did his first strange thing:
The eight “Keyboard White Keys” (C,D,E,F,G,A,B,C) you usually trigger sounds with just stopped responding. I can still trigger sounds from the Black Keys (the sharps and flats), but i can hit them “white keys” as much as i want, i won’t get a sound.

As a result, i also cannot access to the respective “Function” menus of those keys such as:
Kit, Sound, Track, Pattern, Song, Click, Swing, Global.

What i tried:

The Test at start-up gave 0 Error.
The lights above the “Notes white keys” DO light up however in this test procedure.

I tried a factory reset but it didn’t work either.

Has something like this ever happened to you and can you guide me to a way to get them notes white keys to work again?

Thanks in advance!

Pierre-Henri

Whilst awaiting any replies here, it would make sense to ask support if this is an indication of something known/obvious to them - it may be a straightforward diagnosis and remedy - best getting it straight from the horse’s mouth as they say