Xerath's Arcanopulse causes ping spikes upwards of 900 and his ult does not work as intended

Ever since I bought Xerath a couple weeks back, for some reason my ping would be normal until I use his Arcanopulse. My ping would jump from 110-120 to 800-900. There's no logical explanation for this. I assume it's tied to the charge mechanic, but I haven't tested this phenomenon with Varus, for example. As for Xerath's ult, if you press R to enter the ult state, and as quickly as you can press R again to fire a shot at the cursor's location, the first shot will instead fire directly at Xerath's feet. Both of these are incredibly irritating, as they have cause me to lose lane and teamfights, as well as make the game a general nuisance for me. I rather like the mage archetype, especially Xerath and Vel'koz, and I'd very much like to see these fixed as soon as possible to allow me to play one of my two favourite mages. Thank you for your time, Pope Charles IV/Borederly