Varus E invisible (Visual Bug)

Hey, I played against a Varus last game and 2 or 3 times when he used his E, there was a Visual Bug. The first part of the E when Varus fires his arrows was like normal, but the Desecrated Ground was a bit delayed, like 0.5 seconds or so. I know that there is normally a delay until the Desecrated Ground appears (I own varus myself), but this time the delay was between the point where the arrows land and the Desecrated Ground. Suddenly then after a brief delay the Desecrated Ground is there. I play on Medium graphic settings. Unfortunately I have no screenshot.