DDJ-400 headphone volume level issues

Hi! I am having issues with the headphone volume.  Playing a song on deck 1 through the Master output, as I want to listen to my cued up song on deck 2, I click the Cue button above slider 2, but am still hearing Deck 1 very loudly in the headphones and am barely able to hear deck 2. I have the headphone nob all the way over the Cue but still am hearing the master extremely loudly.... not sure why? Please help!

(its not an issue with song volume as Ive tried with several different songs and still the same issue)

Thank you!!