Keyboard buttons not working properly

I'm unaware of what triggers this bug, but every once in a while when I load into a game none of my keyboard buttons work. I can't cast spells or level up abilities with my keyboard shortcuts. The only way for me to interact with the game when this happens is to click with the mouse. Usually when this happens I can resolve the issue by quiting out of the game and back to the client then reconnecting, but I just had a game where this issue happened each time I loading back in. I missed the first 7 minutes or so of a ranked game, and since I was trying to connect my team didn't get a chance to remake. I eventually loaded back in normally after restarting the client, something I normally don't have to do, but at that point the enemy team was too far ahead to really do much to help my team and we eventually lost. I'd really like to avoid anything like this happening again, but I have no idea what the issue might be and how I might prevent it from ever happening again.