My guess is the results of an engraver returning back to his workbench after having too much wine at lunch, where he was previously working on a stock reverse with an engraved denomination and serial number 3, at which time he engraved a 5 on the obverse in error and also not realizing he didn't previously complete the scroll by adding "CERCLE DE LA PRESSE" and placing it with the finished plaques and later shipped off to the club where it was eventually noticed and removed from inventory and possibly placed in a desk drawer where it remained away from the gaming area for however long.