A prisoner thought to have been freed mistakenly was actually found to have been released lawfully after additional checks were made, it has been revealed.
Meanwhile, another inmate released in error is now back behind bars.
It means the current total of prisoners at large after being let out in error stands at two, justice minister Lord Timpson told Parliament.
He noted, however, that “things can change quickly”.
The Labour frontbencher said the blunders were “symptomatic of a system stretched to its limits”.
Data released by the Ministry of Justice on Tuesday showed 91 accidental releases took place between April 1 and October 31 this year.
The problem has come under the spotlight after the debacle that led to the freeing of sex offender Hadush Kebatu, the now-deported migrant at the heart of asylum hotel protests in Epping, Essex.
Stronger security checks were announced for prisons and an independent investigation was launched in response to the controversy.
Justice Secretary David Lammy told MPs earlier this week that three prisoners were currently at large after being released in error, while officials were investigating a case of a potential release in error on November 3, and the person may also still be at large.
The Deputy Prime Minister said that none of the three confirmed were convicted sex offenders, according to their prison records, and that two were British nationals and one was a foreign national offender.
Updating peers on Thursday, Lord Timpson said: “I can now tell the House that the potential case to which the Deputy Prime Minister referred was indeed a release in error.
“I can also confirm that this individual was swiftly returned to police custody on the same day and returned to prison the following morning. I thank Leicestershire Police for its diligent work.”
He added: “Finally, the foreign national offender, who was one of the three the Deputy Prime Minister referred to, was today classified as a lawful release, following additional checks that took place.
“What I have just set out means that the current total of releases in error from prison stands at two.”
But the minister went on: “These are all operational matters and, as I am sure noble Lords appreciate, things can change quickly.”
Lord Timpson told the upper chamber: “Releases in error are symptomatic of a system stretched to its limits.
“Prisons are full, almost to breaking point, which makes them an even more challenging environment. I pay tribute to the prison staff working under incredibly difficult circumstances.
“What we are talking about here is a paper-based system, with individual prisoners’ sentences worked out every time they arrive to a new prison.”
Highlighting cuts to prison staff under the previous Tory government, the minister said: “That is around 6,000 fewer people. The knock-on effect is that, today, over half of frontline prison staff have less than five years’ experience. That makes mistakes more likely.”
He went on: “The previous Government had 14 years to sort this problem out.
“The reason they did not is not because they did not try, it is because it is a complex and difficult task.
“I have taken on this challenge and what we are putting together is a sensible and achievable plan.”
Labour former home secretary Lord Reid of Cardowan said: “I am certain that under previous secretaries of state for justice and home secretaries, including me, there have been frequent inadvertent releases of prisoners.”
Former top legal adviser to successive prime ministers Lord Carter of Haslemere said: “Prisoners have been released in error for decades. I know because I used to advise on sentence calculation in the 1990s in the Home Office legal advisers branch and I was the Prison Service legal adviser.
“It was difficult then, it is now fiendishly difficult because of all the changes to the statute book that have happened since.”
The independent crossbencher added: “The statute book is a total mess as far as trying to calculate when a release date applies for a particular prisoner.
“Prisoners are all in a different position. Some have additional days, some have served a different remand time.”
