Machine doubling. Caused by vibration of the die as it releases the coin. Defined by flat, shelf like second image.
Don't feel bad at your self , it takes quite a while to learn about error coins and how the mint process works. I remember when I started out I thought every coin I found that looked different along the edge of the letters was a doubled die. Once you become familiar with the differences in the appearance of mechanical doubling and a real doubled die coin it will become easy for you to know what you have. A real doubled die coin is produced from a coin die that got the design doubled on it during the making of the die. this is why coins from a doubled die will be exactly identical. mechanical doubled coins will have slight differences between them and with flat shelf like doubling along the design edges.
