This is cut out from the 1947 souvenir sheet that celebrated the centennial of US stamps. It was purposely printed in a different color from Scott #2 with little initials added above the bottom frameline reading BE&P (Bureau of Engraving and Printing). This is a valid 10c stamp even when cut from the souvenir sheet.

US#948
Thanks for not jumping to the idea you had a rare color error of a mint #2.