Since I updated my MBPr to el capitan i have been having issues with my controller. First, everytime I play anything (serato, iTunes, youtube) through the controller to my monitors, the balance tends to the left speaker, meaning that the left speaker is louder than the right. Second, every time I play anything through my monitors (see above) i hear what's playing on the left speaker of my headphones even when cues are turned off. This does not change unless I turn the headphone mix knob completely to master, even when turning master cue on the left headphone speaker is clearly louder than the right one, only when I turn the cue of the track playing through the monitors on does the balance issue on the headphones correct itself. I want to note that when playing music through another source than through usb from my computer (aux in, mic, etc) I don't have this issue. When playing through line in to the first deck, I don't hear anything through my headphones until I turn on the cue of the deck.