Two brief excerpts from The Magical Congress of the United States of America (MACUSA) By J.K. Rowling on Pottermore state the following:
The Magical Congress of the United States of America, known to American witches and wizards by the abbreviation MACUSA (commonly pronounced as: Mah – cooz – ah) was created in 1693, following the introduction of the International Statute of Wizarding Secrecy.
It was in Washington that President Elizabeth McGilliguddy presided over the infamous ‘Country or Kind?’ debate of 1777.
More to the point how did a team of writers, advisors, editors, etc. not notice this glaring error? Have any comments been made by Rowling or her team regarding this?