It could be even more pronounced in some urban areas where Democratic votes are concentrated and ballot rejection rates trended higher during this years primaries.
Amy Campbell, a 26-year-old University of Pennsylvania medical student, had her ballot rejected for another reason: a missing signature.
Vote-by-mail rejections could be of special concern to Democrats, who have seen a surge in absentee ballot applications this year.
For its analysis, the AP also collected absentee ballot data from Arizona, Colorado, Florida, Michigan, Ohio and Wisconsin.
All have had absentee ballots rejected at higher rates than white and more experienced mail-in voters.