Many of these cases could be simple tabulation mistakes in a precinct caucus that otherwise went smoothly, like a West Des Moines precinct that reported the first alignment results only for the “nonviable” candidates (those who didn’t meet the 15 percent threshold) but still reported final alignment results for the viable ones. Others appear to be more serious.

At the next step in the process, each precinct allots county delegates based on final preference, and these county delegates are reported to the news media as “state delegate equivalents,” which approximate the number of delegates won at the state convention. Each precinct caucus gets a set number, but a handful of precincts allotted more state delegate equivalents than they had available.

Notably, there are dozens of precincts where there is a discrepancy between the final preference vote and the number of state delegate equivalents allotted. This includes more than 15 cases in which a candidate received fewer state delegate equivalents than another despite receiving more votes in the final alignment.

In these cases, it is not obvious whether the state delegates or the final alignment results were reported inaccurately.

The Iowa Democratic Party has corrected some errors, but the errors became far more frequent on Wednesday as the count dragged on.

On Wednesday afternoon, the Iowa Democratic Party released a wave of results showing Deval Patrick sweeping central Des Moines. That was incorrect. Mr. Sanders’s votes had been reported as being for Mr. Patrick, while Elizabeth Warren’s tallies went to Tom Steyer.

A plausible explanation is that an Iowa Democratic Party staff member accidentally copied the results of one column too far to the left in a spreadsheet for some precincts. Such errors inevitably occur in manual data entry, but the Iowa Democratic Party does not appear to have enough quality checks to assure that it reports accurate results.