I searched the forum and this isn't the typical issue found of "why isn't it adding?"

Rather, the issue is that, if you have Dual Wield selected on any weapon it adds a +1 to AC even if the 2nd weapon isn't equipped.

For example, select the Dual Wielder feat and then:

1. Add a warhammer
2. Add 2 handaxes
3. Equip the warhammer
4. Observe the AC
5. Do not equip the handaxes
6. Modify the handaxes to have the Dual Wield property checked.
7. Observe the AC.

The AC goes up, in my case.

Huh. Confirmed. AC gets +1 as long as a weapon is set to dual wield, even if you don't equip it.

Thank you for the report! I have raised a ticket for this issue. Currently, it looks like you would need to remove the 'Dual Wield' checkbox to reduce the AC.