Has there ever been an instance of where a typographic error or omission on a paper ballot led to a delay or postponement of an election? I would assume that filing deadlines are set in part to allow for ballot preparation procedures that preclude this kind of mistake. I'm asking in a U.S. context, but anecdotes from anywhere would be welcome.
The Canadian town next door to me voided an election for school board trustees after it was discovered two candidates were left off the ballot. A special election was called a month later.
I believe this is normal policy in Canada.
Since you asked for anecdotes...
About 25 years ago, I was a member of an electoral comission for the student's parliament at a German university. (These parliaments are prescribed by state law.) As part of my duties, I had to prepare the paper ballots. For that, I programmed a database that treated the ballot as a special report, to be used as a master copy for printing.
That report had, it turned out, an error: For each list standing for election, the first three candidates had to be listed by name and in the order filed by the list, in a scheme of open party-list proportional representation. But instead, the names that were printed were random, unordered members of the list.
The problem was only spotted long after the ballots were printed, and after more than a hundred of them had been sent to applicants for postal voting. Brought to the attention of the university's legal department, which had oversight over the election, the election was stopped and all filled-in ballots sent already back by postal voters had to be destroyed.
The election was repeated six weeks later with new ballots, at extra costs of several ten thousands D-Mark (mainly for sending election notifications to all students). A obligatory two-person rule was introduced for the preparation of all printed material in connection with the elections.