Problem with traktor S2 Mk2, Traktor 2.6.8 and my old Mac with OSX 10.9.5

Hi everyone!

I have a problem with my consolle. Now I have a used S2 mk2 but 2 months ago I had a S2mk1 and It totally worked with his software 2.6.8. and my old (but gold) Mac.

Unfortunately my old consolle had hardware problems and I had to change it. My problem is that while I'm djing, sometimes when I'm pushing cue botton or play or similar, the "A" and "B" button of the consolle turn on together for a millisecond and the music stops for that moment, then the music starts playing again. It happens sometimes, not always.

I know my Mac it's old but It worked perfectly with my MK1 and I don't understand what happened, considering I'm using the same software version.

Please help me!!!