Device is off but screen is not? Surface Pro 3

[rpn]

Hi,
I have noticed that my Surface Pro 3 doesn't really turn off the screen when I shut down the device. I'm on Windows 10. I've had the Surface for 3 years now and I think I would have noticed this problem. Or is this normal and I've just never paid attention that it's not totally black? Please have a look at the photo to see what I mean.

I couldn't find any other threads talking about such a problem.

Any advice?

thanks,
A.