Urgot's ult - gameplay

Lately i have been encountering an issue with Urgot's ult. early on in the game, when your ulti is rank 1, his ult works fine. but as the game progresses and you get his ult to rank 2 and 3, it appears there is a bug. when ulting people, you suppress and then switch places with them. However after rank 2 and 3 his ult will suppress and not switch places and fear surrounding enemies, leaving his ult only half used. This is not caused by anything canceling it, my friend and i went into a custom game and tested it. i press R on him and took my hands off the keyboard, and the ult didn't finish.