Abilities Somestimes Don't Work

Please help! I've been encountering a strange bug recently. At first I thought I had spilled juice on my keyboard and buttons R, D, and F were simply not working. This suspicion was cleared when upon trying to cast Teleport to lane, the selected turret's outline began to "glow" as it normally does when it is targeted by an action. However, the teleport did not activate. I continued pressing D and watched the outline expand at every button press. To get the tp to work, all I really had to do was stop pressing for a few seconds and try again. If this were the only problem, it would be playable. However, this glitch also happens when I set Flash to F, and when I try to cast Riven's Ultimate (first cast in particular). This glitch could have something to do with allies being nearby, as it seems to affect me more often when I am getting a gank or teamfighting. This glitch makes certain moments impossible to play, and it happens in both normal and ranked games. Any help would be greatly appreciated.