This happens every year, and it is already happening this year. It doesn’t mean the machines are rigged:

The Alamance County Board of Elections will recalibrate the voting machines at the Graham early voting site after a second-hand, anonymous complaint.

A man claiming to be a concerned citizen called the Times-News and said that when a friend of his attempted to vote for Democratic candidate Hillary Clinton, it selected Republican candidate Donald Trump. The information was left in a voicemail with no return phone number or name of the individuals involved.

Alamance County Board of Elections Director Kathy Holland said she received a similar phone call from one of the local political parties about a man claiming the machine had selected a different presidential candidate from the one he was attempting to select. No one, she stressed, has complained while voting. She said they would recalibrate the machines after voting ended Monday evening at the Youth Services Building.