I agree, I am getting tired of how long this particular track is dragging along, it doesn't make any sense that Arti never ever brought up Aman to anyone. Or brought up the fire where all of Arpita's memories were demolished- she sounds horrible for not bringing up all of these things herself.
Personally I don't think Prasant has anything to do with Yash's anger. All of Yadh's flashbacks are to Arti In the rain, it is a personal and even erotic memory he keeps coming back to, something he can't stop thinking about.
My theory? He finds Arti's diary (as a former poster mentioned) and finds out that she has fallen in
Love with him. This is a betrayal to him,he had told her that his heart belongs to Arpita only. He has realized he is falling in love with Arti and he is upset with himself and with her. Something psychological like that. I think the Prasant track will be huge and until Yash and Arti fall in love, I don't think the CV's will go there. I guess we will find out tomorrow!