In game keys don't work

So, just lost literally any chance of winning a game due to this stupid damn bug. Load into the game, can use ENTER and ESCAPE to access the menu and type in chat (Where the keys work btw), and then reload the game several times before realizing I need to restart the entire glitchy client as a whole.

The issue clearly is not my computer or keyboard as I can type and use my keys perfectly fine still, in addition to a restart of the client fixing the issue. Upon bringing it up another player in chat tells me they've encountered this before as well, and I find out my brother has had the same issue on his computer as well at times. As far as I'm aware its not due to a conflict with any other programs (I do not use any overlays or anything that interacts directly with League), so does anybody have any idea what causes this issue?