A state spokesman said the voter told election officials of the problem. Video of the glitch was widely viewed on YouTube.
Officials said the voting machine was recalibrated and returned to service.
Pennsylvania was also the scene of confusion over voter ID requirements. The state this year enacted a new photo ID law but it was put on hold for the election by a judge amid concern many voters would not be able to comply on time.
Barry Kauffman of the public rights group Common Cause said election workers in many places were demanding IDs even though they are not required. It was unclear, however, just how many voters may have been turned away or discouraged.