Many journalists and writers have written about Kumar's seemingly eccentric behavior. He placed a sign that said "Beware of Kishore" at the door of his Warden Road flat. Once, producer-director H. S. Rawail, who owed him some money, visited his flat to pay the dues. Kumar took the money and when Rawail offered to shake hands with him, reportedly Kishore put Rawail's hand in his mouth, bit it and asked "Didn't you see the sign?". Rawail laughed off the incident and left quickly. According to another reported incident, once Kumar was due to record a song for producer-director G. P. Sippy. As Sippy approached his bungalow, he saw Kumar going out in his car. Sippy asked Kumar to stop his car but Kumar increased his speed. Sippy chased him to Madh Island where Kumar finally stopped his car near the ruined Madh Fort. When Sippy questioned his strange behavior, Kumar refused to recognize or talk to him and threatened to call the police. The next morning, Kumar reported for the recording session. An angry Sippy questioned him about his behaviour the previous day but Kumar said that Sippy must have dreamt the incident and said that he was in Khandwa on the previous day.