Reply to Traktor preferences with the Z1

I can't see the woods for the trees here, but when I load a track into Traktor and press play, the track will play out no matter if the pitch fader is up or down on the Z1. I've been through the preferences to see if I can turn this off but to no avail. I turned off and on "reset all mixer controls", believeing that was the cause but that's made no difference.

Any ideas? Thanks in advance.