Tahm Kench W Bug

I have been playing Tahm Kench (like everyone else im sure) and I encountered a bug when playing against Yorick . If Yorick ults, dies, and becomes his ult. Then you eat him Tahm Kench will slow down and discolor, but not actually eat the Yorick. When you spit what should be his ult clone out, nothing comes out and it does 0 damage. I played a game not too long ago where this happened 4-5 times. Hopefully this gets fixed cause that means tahm has a major weakness against Yorick.