There is nothing to fix, the function works the same way in Arma. The crosshair points to the middle of the screen, which aligns with the bullet trajectory at a certain distance. Contrary to many shooters, the bullet in Arma is actually fired from the muzzle of the weapon, so in very close range, the bullet basically has not enough distance to reach the middle of the screen. The adaptive crosshair compensates this, because it tries to actually represent where the bullet will hit according to terrain features at which a player aims. If a player turns the adaptive crosshair off, they are required to have the so called muzzle awarness, since they cannot always rely on the crosshair alone.