Then, around 10:30 p.m., the board finally released a statement, explaining that it had failed to remove sample ballot images used to test its ranked-choice voting software. When the board ran the program, it counted “both test and election night results, producing approximately 135,000 additional records,” the statement said. The ranked-choice numbers, it said, would be tabulated again. The extraordinary sequence of events seeded further confusion about the outcome, and threw the closely watched contest into a new period of uncertainty at a consequential moment for the city. For the Board of Elections, which has long been plagued by dysfunction and nepotism, this was its first try at implementing ranked-choice voting on a citywide scale. Skeptics had expressed doubts about the board’s ability to pull off the process, though it is used successfully in other cities.