Sona Q Causing Lag [GAMEPLAY]

I started playing Sona a couple days ago, and in every game I've played, the first Q I cast (only the first, and none thereafter) causes lag and a huge drop in fps for a second. It happens in every game I do it, and it effects everyone in the match, even the other team. My friends and I have queued up to play in a party, and they confirmed it lags them as well.