Nashville reporters Kim Kruesi and Jonathan Mattise broke the news: After redistricting, hundreds of early voters in Tennessee’s state capital were sent to the wrong congressional districts, jeopardizing election integrity.

The first sign of trouble came when Kruesi was given conflicting information from state and local election officials about where she was supposed to vote. The confusion arose after Republicans redistricted Nashville, a left-leaning city that was carved three ways in hopes of flipping a Democratic seat.

Kruesi and Matisse started reporting on the mixup and alerted election officials, who confirmed that more than 200 votes had already been cast in error for U.S. congressional and state legislative races. That number grew to more than 430 as election officials scrambled to fix the problem, and a lawsuit prompted by AP’s reporting said the number could ultimately reach into the thousands.

The state’s lieutenant governor and a local election official both thanked the AP for its reporting as they moved to address the issue by allowing the affected voters to submit provisional ballots on Election Day. But concerns lingered that the misstep could discourage voters from casting an Election Day ballot in an election they might see as tainted.