Chester Arthur fudged his birth date.
Chet Arthur’s father’s not being naturalized as a U.S. citizen until well after Arthur was born was not known to anyone having any conception of that combustible fact’s (potential/arguable/well-warranted...your milage may vary) impact on Arthur’s NBC status until Leo Donofrio learned of that fact in December, 2008 and promptly closed the loop with a definitive blog post.