Basically, Honduh over-engineered shit to the point of lunacy on these bikes. If I had the energy to strip it down and separate the brake system, I would. It's just easier to push the rear brake pedal every time I want the front brakes to function.
This is what I found for the GL1800. Crazy stuff to me, but it explains why I always feel the need to use both brakes when 2 up.
Thanks @Pauly for the edumacation.
Page 123 of your Owner Manual states the front lever operates the front brakes and a portion of the rear. The rear pedal operates the rear and a portion of the front.