Union County Clerk Joanne Rajoppi says she found errors in a handful of machines when trying to verify returns.
The numbers from the cartridges that print out vote tallies and the paper-tape backup didn't match.
Rajoppi told The Star-Ledger of Newark that colleagues detected similar problems in paperless voting machines in Bergen, Gloucester, Middlesex and Ocean counties.
The discrepancies have rekindled concerns over the reliability of 10,000 Sequoia Voting Systems machines used in New Jersey.
Sequoia technicians suspect a corrupted computer chip.
Information from: The Star-Ledger, http://www.nj.com/starledger