this is not an error as such. If you have a charlton paper-money catalog it is mentioned on p.309 (25th edition) 1986 5$ notes Bonin-Thiessen with GPF, GPG, GPH, GPL and GPW have been discovered with slightly out of register back plate numbers. This is the case with yours. They aren't considered out of the ordinary but are selling for about $50 in UNC. Hope this helps.