New Jersey Gov. Mikie Sherrill (D-NJ) recently revealed that a software error in the state’s Motor Vehicle Commission registered roughly 6,600 noncitizens to vote after they answered “no” when asked whether they were U.S. citizens. About 400 ultimately cast ballots before the mistake was discovered.

No explanation was given by the governor as to why these mistaken registrations were also assigned party affiliations or whether one party received more accidental voters than the other.