I've had this problem for ages and its not to do with the keyboard or pc as i have switched them a few times over these 7 years or so. ALSO ITS NOT STICKY KEYS. When i click a button it either doesn't work or it gets held down until i press the button again. So if i press d (not hold) it would hold it until i press d again. So far the only way this doesn't happen to me is if i mod the game but i just want to play vanilla currently.
Comments 4
From what you described it’s almost as if a third-party utility is intercepting your key inputs when Minecraft is open and in full screen, so I would check to make sure that isn’t the case. In any case, if the issue happens reliably on a single system but no steps can be given to reproduce it elsewhere, I do not think that can be considered a bug with Minecraft itself. If you have any information that would help others to be able to reproduce this then please share it; if it cannot be confirmed by others, then this report will be closed since it is (seemingly) a tech support issue rather than a game issue.
https://www.minecraftforum.net/forums/archive/legacy-support/1808283-keys-keep-sticking-only-in-minecraft it seems this has been happening ever since 2011