According to The Hollywood Reporter, Whitney had a run-in with former X Factor contestant Stacy Francis that evening, after Whitney failed to remember the aspiring singer after she once pulled her onstage during one of her concerts...

Source: http://www.dailymail.co.uk/tvshowbiz/article-2100025/Whitney-Houston-dead-Whitney-Houston-reportedly-partied-heavily-eve-tragic-death.html?ito=feeds-newsxml