Ghost Poro

During my recent matches playing as Jax in ranked ive noticed I can not place my ghost poro down when hiding in brushes. I am not sure if this is because I am jg placement or if this is due to a bug but so far In 2 matches it counts down to zero as if it is going to place the poro but does not. if someone could help me understand if this is a bug or just my lack of knowledge of the mechanics of ghost poro that would be great thanks!

Kind Regards- LeagueOfLuna