Kalista Ult Bug?
Played a game supporting a kalista as alistar. Every time she ulted I was sent out at max range every time I used it, despite my mouse placement. (Couldn't effectively use it to peel enemies off of her/right next to her.. Just went flying past them) No proof sadly, I don't record my games, but just giving my input in case the issue comes up for others too.
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2102187695/51380953
Match details link in case it is a problem between kalista and certain champ/item in the game