+2 ab given by dual-wielder fighter perk does not stack with mw or gmw

[Spellguard Enthusiast]

Account: Spellguard Enthusiast
Character: Oliver Tattersail

As the title says, the +2 bonus does not stack with magic weapon or greater magic weapon, meaning that if your weapon is enchanted with a +1 the bonus given by the perk is only +1 and if the weapon has a +2, the bonus given by the perk is null. Not sure this is intended.

It is worth noting that I dual wield a double edged sword, that may be the cause.

[Talir]

How did you determine this?

[Spellguard Enthusiast]

Attacking the test dummies behind the Watchhouse, since I never trust the character sheet. I first attacked without magic, and then had greater magic weapon cast on me.

[Spellguard Enthusiast]

Confirmed that this happens either dual-wielding a double edged weapon and dual wielding two separate weapons. Confirmed by account: Teufel Hunden 3.0 character Hamund Barrington. (Hope he does not mind)