While I was browsing for mods, I came across a sneak mod that claimed that the sneak masterperk (ignore armor with a sneak attack) was flawed, and did not work. So it added more sneakdamage.
Another mod claimed the same thing, but said it "fixed" this issue in a different way.

But these are the only references I could find about this "bug". The UESP doesnt mention it. The UOP does not mention it.

So I wonder. Is it really bugged?

Although I could be wrong, as far as I know, it works as advertised. I've never taken the time to test it, but I've never heard of a problem with the sneak master perk working properly.

I suppose it could be tested (on PC) by finding some marauders and sneak attacking them. Then reload and use the command console to remove their armor and see if you can notice any diff.

Sorry can't be of more help.

My sneak just hit 100 in the past session. Here is my experience:

I can one-hit kill a marauder at range, whilst sneaking, as long as I can get the knockdown Expert Marksman effect (my bow does damage over time). It would take two to three shots to take him down before.
My sneak hit 100.
I can now one-hit kill a marauder, no knockdown required. For heavily armored enemies, I do change up my weapons, and usually use an ebony or daedric arrow, rather than the standard Elven, which is the lowest level arrow I carry.
But I just leveled up. So now I can't at the moment, at least I will be able to again, when my marksman skill further increases.

So it does have effect?

I cant really do tests myself. Mods prevent me from doing normal sneak damage

I believe so. But then I leveled up about two walkabouts later. And then I needed more arrows. But I think so. At least, all of a sudden I was surprised by how fast I was taking down ppl and creatures.

Ok.
Thanks for looking into it