As per sources,"Salman is still unhappy and spoke to the producers about his exit from the show. He wanted to abruptly quit but anticipating legal trouble Salman has opted to complete the season and abide by the contract."
The source further added, "Salman, while anchoring the weekend show, raged an argument with Kushal refusing to accept any instructions from the talk back (editing console) and continued to blast the contestant."
It has been said that with Salman its like - Once an enemy, always an enemy. The actor hates Kushal soo much so that he cannot even bear a sight of him and has been heard abusing the contestant behind the sets of the show.
http://www.unitezz.com/confirmed-salman-khan-bigg-boss-8/