I have been playing on around 230~250 ping and I have noticed that shadow shot damage part is very unreliable, quite often the damage part will fail to land on mobs when the character is moving. Even when the character remains stationary through out the cast of the shadow shot, there is a chance (1 in 5) that it will fail.
First half of the video shows using shadow shot when character is moving.
At 0:35 shows using shadow shot when character is stationary through out.