Reply to C - copy to C button goes nuts

Hi, I'm pretty new to this.

I don't know if it's my lack of experience or a glitch. If I'm playing a track on deck 1 and press the "copy to c" button the track instantly plays really fast and then if i stop the track and put a new track on that deck it still goes really fast with the new track, the only way I can change it back to the original track speed is by turning traktor pro 2 off and back on again. Is this a bug / glitch or is it just me doing something stupid ? The same thing happens with deck 2 and "copy to d" button.

It speeds the track up by 50% and if I press the Copy to c button again, it speeds up to 73% but there doesn't seem to be any way out of it.

this is on a VCI 100 SE on a macbook pro

all the best
IPM