Cant Use Abilities [GAMEPLAY]

Sometimes when I play league of legends, I wont be able to use any abilities. This has happened about 3 times, first time with zed, then gangplank, and finally leblanc. This started a couple of days before patch 4.19. This is definitely a client issue, because I can use q w e r on other computer programs, notepad for example. I cant tell you steps to recreate this, because its fairly random, but I can say it happens about every 10 games. Also, it has only happened on Summoners Rift Normals. Finally, when I disconnect and reconnect, the bug is fixed.