Masked areas not affected by global adjustments

[Wid25904354q5fs]

Hello!

I have stumbled upon a problem I can't seem to solve.
I've created several masks for this image, but most importantly - one with "select subject" and then intersected it with "luminance range". This darkened the background, which is what I want, but the problem is that every other normal adjustment doesn't affect the masked area.

As an example I've made the shadows yellow to illustrate that on the top image with masks off, the shadows are yellow, but on the image below the masked background isn't affected.

To my logic, the masks should only be used by the adjusment, targeting the masks, and not the image globally.

Thanks if anyone knows a solution to that!

TL;DR - Is it possible for masked areas not to be affected by global adjustments?

[Bob Somrak]

First of all, Select Subject (I assume was the person) and Intersecting that with a Luminance Range would ONLY affect areas that are IN the subject area and would not affect the background as Intersect is only areas in both mask components.  This would not affect the background at all.

Second, Global adjustments will affect the WHOLE photo with exceptions although certain maxed out sliders behave differently.  

[Wid25904354q5fs]

Thanks for the reply!
I've come to my conclusion a bit too early and it ws not correct.
I was mislead by the sliders I used  - "colour grading" and "Grain", which I tried on another photo.
The adjustment I made with yellow in the shadows doesn't include the very blacks. If I do the same adjustment with the curves the colour change is visible in the background as well. 
What I noticed as well is that lightroom wouldn't add grain to areas of the image which are clipped. This also mislead me and let me to believe that a mask, which I used to make a background pure white, is responsible for that and not the actual luminance values on the parts of the image. 

[Wid25904354q5fs]

I also forgot to mention that I'm aware that after selecting the subject, the background won't be affected, but I've inverted the mask to target only the background. 

Also, feel free to delete this post, as apparently this is not a bug. 
Thanks.