Rengar Immune to Singed Flip during Q Animation

Unfortunately I was not recording the game, but there was a strange bug where when I flung the Rengar as Singed During his Q animation, he continued along his Q movement path, Fling went on cd, and Colassus was not proc'ed even though it was not on cd. Sorry I can't give visual evidence, but please keep an eye out for this if it was not intentional for rengar to be immune to cc during his main attack. Thanks