Most of the so called deer ducking the arrow happens at 15 to 20 yard shots. Deer react to a noise by dropping straight down and then bounding away.
Most of the time the deer that is able to actually duck an arrow was already alerted by something else, strange noise, strange odor, or movement.
The key to avoiding this is learning to be patient and take shots at only relaxed deer. Not many will do that though they think they can aim low or speed the arrow in there before the deer reacts. Sometimes it works (aiming low) but many times the results is a miss or worse yet a fatally wounded deer that is not found.
Deer out farther than 25 yards say 30, 40, or 50 don't react the same way to a noise as they will if it's closer in their comfort zone but you still need to shoot at only relaxed animals. Experience killing animals will teach us all a lot if we just pay attention.
Dan