A highly respected Iowa poll that was canceled from being released amid integrity issues had Joe Biden in fourth place, which could have drastically altered the news cycle and voter considerations in the days before Monday's Democratic caucuses.

According to leaked results verified by FiveThirtyEight, the final Des Moines Register/CNN/Mediacom poll of likely Democratic caucus-goers before Monday's first-in-the-nation caucuses had Vermont Sen. Bernie Sanders leading with 22%, Massachusetts Sen. Elizabeth Warren in second at 18%, former South Bend, Indiana, Mayor Pete Buttigieg with 16%, and the former vice president in fourth with 13%.

The poll, often called the "gold standard" measure of Iowa, was scheduled to be released Sunday, but after an Iowa City man contacted for the poll reportedly complained that Buttigieg was not listed as an option when asked about his preferred candidate, officials did not release the results out of an abundance of caution.

"Today, a respondent raised an issue with the way the survey was administered, which could have compromised the results of the poll. It appears a candidate’s name was omitted in at least one interview in which the respondent was asked to name their preferred candidate," Des Moines Register executive editor Carol Hunter said in a statement Saturday. "While this appears to be isolated to one surveyor, we cannot confirm that with certainty. Therefore, the partners made the difficult decision to not to move forward with releasing the Iowa Poll."

Biden is in second place in the RealClearPolitics average of Iowa polls, with 19.3%, while Sanders leads at 23%, Buttigieg is in third place at 16.8%, and Warren is in fourth with 15.5%.

The last Des Moines Register/CNN poll from mid-January also had Sanders leading the field and Biden in fourth place: Sanders at 20%, Warren at 17%, Buttigieg at 16%, and Biden at 15%.

Iowa caucus-goers choose their Democratic presidential candidate preferences Monday night.