DJM 2000 problem

I purchased the DJM 2000 shortly after it came out. It's an awesome mixer. However, I have had a weird problem with it since I purchased it that I thought had been corrected via the last update. The problem is that the mixer will no longer cue the tracks properly. Both tracks can be heard through the headphones and turning off the cue buttons, lowerint the cue volume or moving from master to cue has no effect. The mixer has to be turned off and turned back on again for it to work properly. This doesn't happen often but it can happen at a gig like yesterday. Another strange thing that happend yesterday after the issue started is that I lowered the master volume all the way down but the music kept playing, I then turned the channel slide down and that worked but cutting the master volume should have done it too. Any help with this would be greatly appriciated. Thanks.