In a preview of what promises to be a big theme during 2024's presidential election, local voting problems on election day ignited allegations of fraud by Donald Trump supporters.
Mr Trump has consistently made false claims about widespread voter fraud costing him the 2020 election.
Tuesday's incidents were scattered around the country.
Mr Trump did not publicly comment on the allegations, but they were spread by some of his online backers.
Kentucky gas leak, police chase
Two polling locations in Louisville, Kentucky were ordered to stay open for 30 additional minutes on Tuesday night.
A gas leak temporarily shut a polling location at Highland Baptist Church, while another location at Blue Lick Elementary School was also briefly closed due to a nearby police chase.
As a result, a judge ordered both locations to briefly stay open to comply with a state law that requires polling places to open for a total of 12 hours.
The incidents were seen by online partisans as potential proof of fraud. In just one post viewed almost one million times on X, a Trump supporter commented: "Both the polling locations are in areas where democrats gain a ton of votes. It appears Democrat Beshear just may find the votes he needs to win tonight. It never ends."
But Erran Huber, a spokesperson for the Jefferson County Clerk, told the BBC that exactly one person voted across both locations during the extended half-hour opening period.
"Any claim that there was election tampering at either location is patently absurd," Mr Huber said.
Mr Beshear won re-election as the state's governor, beating his Republican opponent Daniel Cameron by more than 65,000 votes.
Voting machine problem in Pennsylvania county
A voting machine bug appeared to flip votes in one county in Pennsylvania.
The error occurred in ballot questions asking whether two state judges should retain their seats. Voters marked "yes" or "no" on each of the two candidates - one Democrat and one Republican. The machine appeared to swap the answers on a summary screen.
Once again, news of the glitch was seized upon by Maga activists as proof of a larger "voter fraud" conspiracy.
One commented: "Voting machines have been SHUT DOWN at multiple state election locations due to errors, reports of 'votes getting flipped.'"
The problem was flagged up by voters in Northampton County shortly after the polls opened on Tuesday. County officials said in a statement that paper records would be used to correct the tally. State officials said the problem was limited to the two candidates and to Northampton County, and that no other areas or races were affected.
Voting machine problems in Houston
In the Houston area, voting machines broke down at several polling stations, the Houston Chronicle newspaper reported on its election day live blog.
Other machines at the locations continued to operate, although in some cases the result was long lines for voters.
The paper reported that at one location, about 20 voters left a queue before casting their ballots.
Again the issues prompted viral online rumours, but there was no indication the problems affected the outcome of any of Tuesday's races.
The BBC contacted Harris County officials for comment.
Connecticut ballot box
Among the rumours and baseless claims, there is one election in Connecticut which has been the subject of potentially credible allegations of vote tampering.
Last week, a judge voided the results for the Democratic primary for mayor of Bridgeport, a city of about 150,000 people, after videos emerged of women inserting large numbers of ballots into a drop box. Connecticut law only allows family members or other close contacts to drop off absentee ballots in this way.
Incumbent mayor Joe Ganim won the September primary by 251 votes over challenger John Gomes.
Mr Ganim appeared headed for a similarly close win in Tuesday's general election, but the election may have to be re-run, pending the final outcome of the court case.
Mr Ganim has denied wrongdoing. Both Mr Ganim and Mr Gomes are Democrats.