Pioneer DDJ-1000 Master Cue not working properly

Hi,

I just bought my Pioneer DDJ-1000 and I'm trying to listen to what comes out of the master output through my headphones. From my knowledge, the master cue option should allow this. However, when I have that selected, along with the "Headphone mixing" turned all the way to the right for Master... It plays deck 2 as well. This is even with the cross fader all the way to the left for deck 1. But, when the cross fader is all the way to the right for deck 2, it does not play deck 1's audio. Is there something I'm doing wrong?