An editorial review of RTE's controversial Frontline presidential debate has identified a series of failings in the production and broadcast of the programme.
But the probe concluded that the mistakes were not made as a result of bias or partiality.
RTE said it accepted the review findings and expressed regret at the errors flagged up.
The programme in October 2011 dealt a hammer blow to presidential front runner Sean Gallagher's chances of victory in the election after it broadcast a Tweet from someone falsely claiming to represent rival candidate Martin McGuinness.
The Tweet, which was not sent by Mr McGuinness's campaign team, claimed a man who allegedly gave Mr Gallagher a cheque for a Fianna Fail fundraiser would be presented at a Sinn Fein press conferences the following day.
This heaped pressure on independent candidate Mr Gallagher to explain his past links to Fianna Fail.
The Broadcasting Authority of Ireland (BAI) subsequently upheld a complaint by Mr Gallagher and ruled that the programme had been unfair to him as it had not established or made clear the unverified nature of the Tweet. RTE accepted the BAI finding and apologised to Mr Gallagher.
The editorial review commissioned by RTE in the wake of the BAI investigation did not specifically examine the Tweet issue as it was subject to a separate personnel investigation by the state broadcaster.
Instead the review team, chaired by former Ulster Television head of news Rob Morrison and RTE's director of programmes Steve Carson, looked at the overall editorial processes of the Frontline programme.
They concluded: "While the review identified a number of mistakes in the preparation and in the broadcast of the programme, we noted that the production team had worked conscientiously to deliver a robust but fair debate. The mistakes made in the programme were not the result of bias or partiality."