Fenix 6X backlight not working

The backlight has been flickering on my Fenix 6X for a month and now it does not work at al  

Also when i press the light button it makes a different sound to all the other buttons. Like a dull beep and not a sharp beep like the other buttons. 

The watch is becoming unusable now as i can only see the screen in good daylight  

Is this a software issue? Version 19.40