Hi, Welcome to the forums
It would help a lot if we knew the dates of those coins. My own thoughts are
1) the "different" coin may be a high grade compared to the other 3, whose edges look pretty worn.
2) it's even possible that the different coin is a proof (is it dated 1937?), whose edges are sharp and crisp and even (I sound like good king Wenceslas ) compared to currency coins.
Picture of the reverse of all 4 coins would be helpful.