Jayce's Ultimate Toggle to Mercury Hammer Causes a Half Moment Lag Spike

There is no issue elsewhere - it is quite simple. When you are in mercury cannon and press R to switch to Mercury Hammer, a half second lag spike comes out. It isn't a huge issue, and I can still play Jayce with it - though I have died twice in the past single game because of me not being able to react quick enough after switching Hammer to do what is required for the enemy champion to die before I do. Please smooth this crink out, Riot!!! Jayce is a great champ, and among my favorite - the frame freeze really is an issue though.