Champions simply walking out of Warwicks ult?

Recently been playing as Warwick, and whenever I have ulted on an enemy champion they simply walk away while I'm stuck in the animation of the ult. It recently happened twice in an ARAM match. Not sure if this is just on my end, but wanted to give a heads up to Rito.

Has anyone else had this problem?

P.s. Both times NO other monster, minion, or enemy was near the champion I selected.