DJM-900NXS2 MIDI On/Off button does not work (Traktor)

Having tried this on two different DJM-900NXS2 mixers, it's definitely a software issue:

As soon as I startup Traktor, the MIDI ON/OFF button becomes green (USB A or B, whichever is plugged into the computer). Subsequently, pressing the on/off button does nothing - it simply stays green (ON).

The trouble is, using mixer knobs also controls the Traktor tracks (track fast-forwarding, etc.). I am simply wanting to use the mixer to output the audio from the 4 Traktor decks, but don't want it to be a MIDI controller sending signals into Traktor. Currently there's no way to disable that at all. Someone please HELP!

Here's the video demonstrating the exact problem:
https://vimeo.com/204313328