Why is my social security card dated?

I just had to apply for a new card(one not containing the annotation of "valid for work only with DHS authorization". The one i got now is dated. It was hypothetically suppose to be undistinguishabble from the one a us citizen carries. However it isn't because it is dated. I'm a permanent resident who is currently having the conditions removed from my green card. this is making it really hard for me to get a job i've applied all over the place.