DJM900 nxs - keep on having reinstall drivers on Mac to record from mixer

I am running a DJM 900 nxs and Macbook Pro (15 inch mid 2012) with OS Sierra 10.12.1.

I was previously able to record mixes in Traktor Pro with a USB cable connected to the mixer. A couple of months ago the green flashing light below the USB connection decided to keep on flashing as opposed to becoming solid to indicate a proper connection. I hadn't changed any settings on the computer and whilst the DJM 900 settings utility was showing the mixer as connected, Traktor wasn't showing it as an audio source. After reinstalling the driver it seemed to sort out the problem and I was able to record mixes once again. But now it seems that every time I come back to the mixer to record it's the same flashing green light again, another reinstall of drivers, and then its working again. I'm still in warranty by a couple of weeks - should I get it looked at or has anyone else come across this?