I sent in a "support request" for this issue.
and 2 more explanatory emails. because support is not really good at "comprehensive reading" (I don't know why I printed this in small size because Arturia is not reading this anyway.)
After a very frustrating email conversation, it ended in "Computer Says NO!".
The status LEDs ar probably not on PWM outputs, but just on digital outputs of the processor, so a firmware update cannot help us.
DIY MODE:
If you want to dim the LED's, use an EDDING 400 Black.
I tried an EDDING 751 Black, but that was too much, this is not transparent at all.
The Black 400 dims quit a bit, to an exaptable level.
I'm not completely satisfied with the results of an Edding 400 black, it gives the right amount of dimming, but the coverage could be more equal over the entire surface of a led.
Maybe a semi transparant or gray 751 would work.
If anyone has a better suggestion, please post it.
P.S.
Q-tips and alcohol allow for some experimentation....