Have you tried it on the non-Honour ruleset?
I did, and was able to do it, but the problem I found was that nothing showed up differently in the combat log, and it seemed to "unlock" the extra attack feature randomly, which remained "unlocked" until I respecced. I haven't been able to replicate it at all in Honour Mode so I haven't felt like I had enough to write an actual bug report.
Pertinent details...
Wyll(as companion)
Level 5
Hexblade
Pact of the Blade
Shadow Blade
Knife of the Undermountain King(auto dual wield attacks disabled)
I used Withers as a test dummy and it happened while he was Hexblade Cursed by the active skill(not as a result of being hit), alternating between which weapon has the Hexed weapon status. But not on the first attack, it took a few strikes. It worked with both weapons. It makes zero sense and nothing looked different in the combat log, so I don't know useful that is. I'm on xbox, btw.I figured it out, got it to reliably work 100% of the time. Annoyingly stringent requirements, though
1: Honour rules must NOT be enabled.
2: You MUST select Pact of the Blade.
3: The weapon MUST be bound via Hexed Weapon or Pact of the Blade.
4: It's possible to attack with an un-bound weapon(bow), too, but if used first it will eat your entire action.
Balancing Hexblade and Pact of the Blade must be a nightmare. Without a native Extra Attack, Pact of the Blade is pretty much mandatory on a pure Hexblade character. With a native Extra Attack, Pact of the Blade is pointless for a pure Hexblade character.
I've already sent in a bug report detailing all of this.
