What is Nishant's issue with Karan?

I haven't been watching from beginning. And as far as I have seen, KK has always stood by Nishant n haven't done anything to backstabb Nishant. Always went to Nishant to clear stuffs. So can someone enlighten me as on what happened btw them?

I really hope Nishant n KK plays together instead of playing with Prathik n Teja respectively, as those two are short tempered, goes on different tangents at times and can ruin their games.

The episodes r edited in such a bad way that they show fight but not the backstory behind the fight.