Traktor 4 the remix decks only play in loop one shots don’t work on some cell. I even reloaded the samples that wouldn’t play and it does the same thing. Traktor 3 remix decks work.
This is one of the most frequently reported problems.
Then you have to be patient because version 4.0.2 has just been released and it is not fixed there (at least there is nothing about it in the changelog).
You can try it out and see if it's better with the update, otherwise we hope that everything will be fixed with 4.0.3.