Sona making game lag?

Hello, So the past couple of days when i have picked Sona support whenever I first use my Q ability- Hymn of Valor the whole game seems to randomly stop for 1-2 seconds with the screen frozen and then revert back to normal. It apparently also affects other players in the game since I was talking with my friends in Teamspeak and their screen also froze when I used Sona's q at first. It only seems to happen on the very fist cast of the ability. I run flash and exhaust if that helps.