Director AR Murugadoss has made open statements suggesting that Bollywood superstar Salman Khan is unprofessional. He attributed the failure of Sikandar (Hindi) to Salman's alleged lack of work discipline and on-location commitment.
It's extremely rare for a superstar in any Indian film industry to receive brickbats in the open. Small actors have been panned in the past by some industry persons and through planted news articles, but superstars escape all criticism even when they are wrong. Recently, a top Telugu producer had to tender an apology merely for saying that Ram Charan didn't even make a call after the failure of Game Changer.
Since ARM has blamed Salman for the failure of Sikandar, there is a possibility that their relations soured after the movie's disastrous box office performance in the Summer of this year.
After a movie incurs losses, a lot of action takes place behind the curtains. Distributors/producers might enter into a re-negotiation phase with OTT platforms, for example. There might be pressure on the director/hero to return a part of their fee. These negotiations result in soured relations. It's possible that AR Murugadoss was insulted by Salman Khan in this process.
