Name: Treat Knowles
Location: Eastham, MA
Date: 1765
Carver: The Codner shop

Normally I give the names of the deceased as they appear on the stone. Here, I made an exception.~
I've no idea who erred here- whether it was William Codner's doing or possibly a protege of his.
I do know that, as Peter Benes has pointed out
A) sometimes carvers made mistakes out of too much care rather than too little. That is, concentrating on executing a carving to the point where some important detail is forgotten.
And B) a lot of men of the time were way better at working with their hands than their minds. :P