I noticed that when trying to reflect an arrow with a shield, there is a chance to fail blocking attempt, even you right click with shield before the arrow hit you.

I've placed a dispenser filled with arrows and connected it to a pressure plate 6-7 blocks away from the player approximately. Right after pressing on the plate, the arrow has launched, right clicking with shield doesn't reflect it. Ending with receiving normal damage, knockback and shield durability is not reduced. There's a tiny time difference between right click and the arrow. Even the first event is being right click with shield, it doesn't block it.

Shortly, blocking will not work if you right click late, even if you do it before arrival of the arrow and hit you with a tiny time difference shorter than a second.

Also i've already knew that shield would not block after 0.25 seconds being selected, but i thought this is a different situation.