Strange Non-Lag Slow and Late Button Response

So this has been happening since the start of December I'd say of 2019. Previous to that, everything worked perfectly fine. With that being said, I'm not sure if it's a Windows update, a driver update, or a League setting change which might have caused this. But here's a description of what my issue is:

I'll be in-game and press TAB (my scoreboard), sometimes it'll stay on-screen even if I release the button. I'll press it multiple times and nothing happens. Then perhaps a few seconds later it will spam open and close as if I pressed TAB multiple times. Sometimes a similar issue happens to abilities, sometimes abilities will not work, until a second or two later. This feels and sounds like generic lag. Yes, but my ping during those times remains around 45, as it usually does. I see other players moving just fine, and I don't experience the usual stuttering that I do when I truly do get lag with high ping. It's not an FPS issue either as my frames remain the same too, and everything else around my character looks to be just fine.

It almost feels like it's an input issue from my keyboard, but if that was the case, then I'd be experiencing similar issues across my entire computer. But this only happens on League of Legends. I've tried to uninstall the game, and install it again and nothing has changed.

Has anyone experienced this before? Is this happening to others as well? Any ideas how to resolve this?

Thanks.