I was going through an old filing cabinet to which the key had been lost a long time ago and in it I found a marriage certificate for my aunt and uncle for the State of Maryland tho they both lived in Queens on Rockaway Beach then Far Rockaway. The certificate is dated May 12th1958 and I then found another marriage certificate from the City of New York for Oct 24th 1972.

Is it normal for people in the USA to have to get married again in different states?

No, not that I know of.

That is very odd indeed. Assuming there was no divorce and remarrying involved, I don’t see why someone would have a marriage certificate from more than one State.

You are not required to but also nothing to stop you from having a separate one from a different state.

I used marraige license from New Jersey to get married in Maryland (performed ny someone who was recognized by NJ) and got the NJ certificate.

Sometimes it is easier to just get another certificate for your current state. Some agencies have issues with other state certificates and or "cant find it on record".

Maybe the 2nd one didn't involve a shotgun?

they probably lost the first one and found it again, or as someone else mentioned, they may have wanted to avoid the hassle of trying to use an out of state certificate for whatever it was they were trying to do. sometimes local gov't offices can be annoying about accepting ID / docs from out of state when they're not familiar with them.

Thanks for the input guys, I can't ask them as Uncle Vinny passed away in 1976 and Aunt Ina passed away in 1992
They did not get divorced or that and they had lived together since just after WW2 when my aunt emigrated to NY, after Vinny passed away she spent her last years in Buffalo NY and that is the main reason I follow the Buffalo Bills