Tahm kench Yorick bug?

Well recently while i was in a game playing as Tahm Kench jungle I got into a situation where i fought against a yorick. When he died and popped his ultimate I tried to consume him after achieving the 3 stacks of my passive needed (the stacks even showed up and turned red like how it is suppose to). After doing this i attempted to consume him; however i was unable to even after multiple attempts at it. Is this a bug or is it Tahm kench just unable to consume yorick ult? If it is the latter then they need to remove the visual of Tahm kench's passive being applied to Yorick ult.