Mordekaiser Jhin Ghost

I played an ARAM with my friend and there was a on the enemy team. Near the end of the game I got him as a ghost and while we were taking their nexus turrets he just kept shooting his final/fourth shot over and over. I am not 100% if it was dealing the increased damage but he kept yelling four, the animation and all of that. I am not for sure if this was occurring when he was shooting champions or not because I didn't notice it before then so I am not for sure all of the details on this. I just figured this could be obscenely broken if it does pop the fourth shot on champs over and over and so this needs to be looked into.