Djm 900 traktor pro/ maverick

Djm 900 sound issue traktor/maverick

Hi, I am running the latest version of traktor pro on my 2012 i5 MacBook Pro running maverick, and the latest firmware on my djm 900. Sometimes for no apparent reason the sound quality is distorted, I'm using the djms soundcard, when I use my other soundcard this never happens.
It also sometimes makes one speaker go very quiet and the other one normal volume, if I restart the mixer it returns to normal, is this a maverick/djm900 issue?
Please help as iv it's the mixer that's the problem I will return it before the warranty expires.
Thanks