Hi, I recently joined Coneca, as I’ve been collecting US coins some on and off through the years. Of course I started stashing and analyzing 1982 pennies-and saving other 82/83 coins since they were no proof years. I ran into a strange thin quarter with a bronze circle on the reverse and it only weighs 3.9 on my scale. Not a hammered or dryer quarter since the ridges on the side are still intact-but appear bronze- and everything is readable, so I wasn’t sure if it was some sort of experiment, or indeed perhaps a clad error. Pics attached and any insight is appreciated.