The Eighth Circuit determined that checking the box on a I-9 affirming that an applicant is a "citizen or national of the United States," on its own, is not sufficient to establish that the applicant made a false claim to U.S. citizenship. Instead, an adjudicator must ascertain whether the applicant intended to make a false claim. In the instant case, the petitioner had testified that he would lose his job if he wasn't a U.S. citizen, and thus, the Immigration Judge correctly determined that he intended to falsely represent himself as a U.S. citizen.
The full text of Godfrey v. Lynch can be found here: http://media.ca8.uscourts.gov/opndir/16/01/151027P.pdf