Hi Ramza,
I've just detected a bug (I'm on MV) :
With the Barehanded Attack option set to OFF, if my ambidextrous actor has only one hand equipped as a mainhand, he attacks with a punch using the offhand.
I tested this on a blank project, with only YEP_BattleEngineCore and Ramza_dualWield, and didn't touch any parameters other than setting Barehanded Attack to OFF.
This is the last version : v2.75