A mix-up with the House of Commons' official app saw the DUP's Nigel Dodds mistakenly listed as having backed a Labour motion calling for a pause in the roll-out of Universal Credit.
The CommonsVotes app lists how MPs vote, showing each individual vote taken in the chamber.
On Wednesday evening MPs voted on the Labour motion calling for a pause to the roll-out of Universal Credit - a controversial reform that will see six benefits combined into one, something aimed at avoiding circumstances where someone is better off on benefits than working.
The vote was non-binding, and introduced over concerns that many of those on benefits are being hit with six-week delays in their payments.
Conservative MPs were instructed to abstain from the symbolic vote, and it passed with 299 in favour with 0 opposed - with one Conservative MP Sarah Wallaston going against the wishes of her party to side with Labour.
Following the result, the official app listed that one DUP MP had backed the motion.
It later emerged that Nigel Dodds had mistakenly been listed with the ayes, due to a mix-up with Labour party politician Anneliese Dodds.
Earlier in the evening the DUP MP Sammy Wilson stated his party's intention to abstain from the vote, which he said was down to not being "used for headline grabbing defeats of government flagship policies".
Following the vote, Labour leader Jeremy Corbyn said that the government should "act on the clearly expressed will of Parliament".