The companies “uploaded something last night, which is not normal, and it caused a glitch,” said Marcia Ridley, elections supervisor at Spalding County Board of Election. That glitch prevented pollworkers from using the pollbooks to program smart cards that the voters insert into the voting machines.

Ridley said that a representative from the two companies called her after poll workers began having problems with the equipment Tuesday morning and said the problem was due to an upload to the machines by one of their technicians overnight.

“That is something that they don’t ever do. I’ve never seen them update anything the day before the election,” Ridley said. Ridley said she did not know what the upload contained.

Gabriel Sterling, voting system implementation manager in the secretary of state’s office, told reporters that the issue likely was a dataset that got uploaded to the systems, but that they don’t know for certain. He did not say if the dataset was uploaded by the voting machine vendor.

Sterling told reporters the issue took some time to fix because technicians had to bring in additional equipment to correct the problem.

Neither Dominion nor KnowInk responded to a request to comment. A spokesperson for the secretary of state’s office also did not respond to follow-up questions about who uploaded the dataset and whether it had been reviewed and tested by anyone beforehand.

Jennifer Doran, elections director for the Morgan County Board of Elections and Registration, said the issue was with how the KnowInk pollbooks encode a voter access card that is used with the Dominion voting machines.

When voters sign in at a voting location, poll workers insert a voter access card into the Poll Pad tablet and encode it for that voter. The card is then inserted into voting machines to display the proper ballot for that voter. The glitch apparently prevented poll workers from encoding those cards.

“Morgan County poll workers did a great job of quickly moving to emergency backup procedures so that voters were able to continue voting,” Doran said. She said Dominion technicians fixed the issue.

The counties devised a workaround in some cases by having poll managers use their own card and a code to initialize the voting machine for each voter. But this caused long lines at some precincts.

Georgia uses Dominion voting machines and KnowInk Poll Pads statewide — systems that the state only deployed in every county for the first time this year after replacing its previous 20-year-old electronic voting systems. It’s not clear why other Georgia counties did not have the problems Morgan and Spalding had.

Eric Geller contributed to this report.