Thank you for the picture,
I find it strange you have those indicators. When I select OLED Off in Armoury Crate, the display is completely black.
I'm using 2.4GHz wireless mode.
Is Armoury Crate and your ROG Azoth fully updated?
Here are the current versions to compare.
Sure, my camera is pretty bad, but I can show you all indicators are off.
Here is a pic with the OLED display on, the blue tab is the protective plastic film.
Here is a pic with the OLED display set to Off.
After a little test...
So, it seems when the OLED display is set to Off and the cable is connected, it will show the battery charging % when your pc is shut down.
In 2.4GHz wireless mode with the cable disconnected, the OLED display is completely off when my pc is shut down.