Looks like there has been some tension brewing between the two.
According to sources, Sidharth is happy with Alia's career and her film choices but is not happy with her close connection with actor Varun Dhawan. The actress has been seen with Varun back-to-back in few films and has been appreciated by the viewers for their on-screen chemistry. Interestingly, Alia apparently has s big issue with the growing closeness between Sid and his co-star Jacqueline Fernandez.
After Kapoor and Sons, Sidharth and Alia will next be seen together in Aashiqui 3.