Okay, I give up, there's no sense in this.

I don't know if a bug report or request for documentation on how these colors change other colors would help, but I wasted already too much time.

I tried something similiar for the end:

Index color 254. It should be 244,244,244 right?

Well, it doesn't show like that in New Color Swatch.

And this confirms that:

So somehow ACAD decides to change that #254 to 214,214,214.

I'm not sure if this is index color or true color then. Why it doesn't show up listed as 254?

Maybe then: I choose an index color -> ACAD changes it to another -> it is converted to true color -> layer colors do not change their appearance, since it's not inxex color?

Btw, why some grays have names like Vellum? Where can I check or change them? Are they interfering the "normal" acad color system?
EDIT: Seems to be that Vellum is 192,192,192 ie. #9. And Charcoal is 130,130,130, which might be close enough for #8? These color names are naturally totally undocumented.

I just wonder if there are any professionals working with mac version of ACAD?

Is it just a gate for people to switch to windows version, if they are seious about using it?
(By not fixing the installer bug in 2021 really hints that way...)