Was Kartik Aaryan's ugly fallout with Janhvi Kapoor the REAL REASON behind his ouster from Karan Johar's Dostana 2?

Both Kartik Aaryan and Karan Johar have refrained from commenting on Dostana 2 controversy. It is now being said that Kartik had an ugly fallout with his co-star Janhvi Kapoor and their friendship reportedly ended in January.