Reply to CDJ-2000nexus, suddenly PLAY button won't work, "Needle" flashing on screen..

Hey guys, so very randomly, one of my CDJ-2000's stopped allowing me to use the "Play" button.. it just seems like it does a super quick stutter, and the small "Needle" red light on the screen flashes.. when I hit the cue button, it all seems to work fine, until i release cue again.. can anyone help me out here? Thanks!

EDIT: it seems to work again once the other deck has stopped completely.. what gives?