Mundo's Cleavers are Invisible!

Any time Mundo throws one of his Cleavers it is completely invisible until it hits. This is a huge problem, especially as a squishy trying to dodge invisible cleavers, and can often result in death due to the slow. During the match I played earlier, Mundo's cleavers were invisible throughout the match with every through after 7:25. Occasionally one of his throws would appear, but not every time. There wasn't really any consistent variable that appeared to happen just before Mundo threw an invisible (or visible) cleaver.