[Gameplay] Xerath Arcanopulse Charge Lag

In game, when playing as Xerath or any other champion, my client will run perfectly fine. The ping doesn't spike, and it stays at a constant low. However, when I'm charging arcanopulse (Xerath's Q), the ping will spike up only during the charge, causing it to charge longer than intended. If I were to let go of q and fire it while it's lagging, then move my mouse away, the arcanopulse would fire in the direction that the mouse was left on after the ping spike had ended. This happens almost 100% of the time, though when I don't charge it as much or at all, it sometimes won't lag.