A computer science expert who has studied Georgia’s outdated voting machines testified Thursday that inherent defects, age and “repeated security mistakes” by the state made the 2018 election “far more vulnerable than most other states and most other elections.”

A “telltale sign” that votes were tallied by defective machines used during the midterm election last November was a “significant undervote rate” in the lieutenant governor’s race that was bolstered by anecdotal reports from voters who had difficulty casting a vote for that race, said Matthew Bernhard, a consultant on election security for plaintiffs in ongoing civil litigation contesting the validity of the election of Lt. Gov. Geoff Duncan.