Well why could it be missing? The VDB is incuse on the coin. Meaning it is below the normal surface of the design. How does the die create an incuse mark on a coin? The die being a negative of a coin, if it is incuse, then the devices needed to form these devices would have to be raised on the die. Because of die polishing, it removed the raised area on the die. Now the strike on coins after this happens, would be that these incuse devices would be removed. (not visible) This is not a die variety, but a die event. So all coins struck with that die after the devices are removed, so all the rest of the cent struck with that die will not have the VDB. So it is common error, and not listed as it is not a variety coin.