Invisible Dr. Mundo Cleavers

I just experienced a bug where the enemy Mundo's cleavers were invisible. It wasn't just me because my entire team actually said the same thing. He was using the default Mundo skin. I'm not sure if this bug occurs on Mundo skins with different cleavers, like Corporate or TPA.

This bug is a huge deal, because it actually inhibits my ability to dodge the cleavers.