The Nexus machines are no longer used from Vancouver into the US, they have removed them. You must fill out the blue form also and present it with your GE slip.
Wonder how many GE users got burned by that as GE members are told that they don't need the blue customs form when using GE.
Seems like CBP at YVR need retrained on how GE works (as the customs form is filled in electronically at the kiosk).