I recently found out that "t" was no longer knife, but the middle mouse button. Also the "l" was no longer lights for the vehicle. Why change the default keybinds? I was so used to this before. Now "g" is lights, and "middle mouse button" is melee. So sad, got killed for nothing... Now I gotta train muscle memory again. Yes, I had to recently re-load the game.
They moved them to make them more accessible to new players, it was in one the patches long ago. It did not change the keybinds for players that had already installed the game, so your just noticing now as you re-installed.