There are many variables that can happen. I’m not an expert...maybe Spragg could provide more info??

1. The paper used on these 2 cards could be a different stock...taking the stamp differently.
2. The stamping machine might of been hotter during one of the stamps.
3. A die could be more worn after a couple of years? (7 yrs) Maybe a different die?
4. They could of stamped longer or shorter time on either of the 2 cards.
5. Used a different foil.
6. The stamp is most likely a 3 part component. Left wreath ...J.....Right wreath.
They used spacers on some of the stamping. Different sizes. I cannot recall the sizes...but vaguely remember 3/32..1/8.. or something like that.
Here is a sheet that includes some of their stamping styles...