1973 D Lincoln Penny- Mint Mark Questions And Error?

Hi guys,

I am new to the coin community. I show two photo's of 1973 D Lincoln pennies and have a question regarding the 'D' mint mark on the brown 1973 D Lincoln Penny. I noticed that the 'D' mint mark is much smaller and lower than the red coin's 'D" mint mark for the same year. Why is this? I have read that mint mark's are always the same size and in the same position during a given year when minting is done.

My other question is, why does there seem to appear a faintly printed "D" above the word Liberty in the brown 1973 D Coin? What is this? Did something happen in the mint?

Thanks very much. Hope you all are having a good day!