Helldusk Armor bug? 24 AC, not 21 AC?

[Isalon]

Hey all, noticing something with Helldusk armor.
My Gale has an AC of 15 without wearing the Helldusk armor. (Chest piece.)
The Helldusk armor has an AC of 21, and it's heavy armor, so it doesn't benefit from Dexterity. Meaning, when putting it on, the AC should be 21.
When Gale puts it on, the AC is 24.
Gales Dex is 14, so he's only got a +2 bonus to dexterity - so this doesn't look like a Dex-based bug.
Theory: I am wondering if the armor is considered a +3, so it's 21+3=24? That would make sense, although it's not specified on the armor...and should be?

I know some of you are going to go "Why the hell do you have heavy armor on a wizard?"
Well...why not? The armor doesn't require proficiency in order to wear it. A wizard running around with absurdly high AC? Yes please. He has ALL the Helldusk armor and looks like a badass. A simp badass. It's comical.

[Zygfryd]

Just hover the AC shield in inventory and it should tell you the breakdown.

[Phero]

I'm guessing this is a real Helldusk armor and not the flawed one you can get from the blacksmith?

[Isalon]

Originally posted by Phero:

I'm guessing this is a real Helldusk armor and not the flawed one you can get from the blacksmith?

Correct. And thanks Zygfryd, totally forgot about that.
Without armor: 10+2 (Dex) +3 (Shield) = 15
With armor: 21+0 (Dex, heavy armor) + 3 (Shield) = 24
Mystery solved!