Sorry its a typo.
I have the version 1.8.1 of RMMZ. It work fine with the ATB active but not the ATB wait. The character who cast the skill can cast it even if the other member don't have a full bar (it doesn't behave like this in ATB Active) or don't wait for the other character to have their bar filled in order to cast de dualskill. It behave like if the linked parameter wasn't there.