Motorsport's world governing body says "human error" caused the controversial ending to the 2021 Formula 1 season, denying Lewis Hamilton a record eighth world championship.
The FIA released its report into last year's Abu Dhabi Grand Prix just hours before the first qualifying of the new season.
Max Verstappen won last year's final race and world championship when he benefited from a "misunderstanding" of the safety car rules by then-race director Michael Masi.
At the end of a safety car in the final laps of the race, there were eight cars that had been overlapped — five of these cars were between first placed Hamilton and second placed Verstappen.
Masi decided to only let the lapped cars between Hamilton and Verstappen through, not those behind, which should not have happened according to the FIA.
"The process of identifying lapped cars has up until now been a manual one and human error lead to the fact that not all cars were allowed to un-lap themselves," it said.
Masi has already been removed as F1's race director, a role that will now be shared between two people.
However, the FIA admitted its rules could have been misinterpreted the way it was written.
"It was apparent from the analysis that there could be different interpretations of Article 48.12 and/or Article 48.13, and that this likely contributed to some of the confusion surrounding the safety car un-lapping procedure," it said.
Despite the errors admitted by the FIA, the governing body says the results of the race are valid.
With the lapped cars out of the way and Masi pulling the safety car in for the final lap, Verstappen overtook Hamilton to win the race and the title.
The FIA report noted the pressure Masi was under from the teams to not finish the race under a safety car.
It said Masi's efforts to try and finish the grand prix under full racing conditions was "in good faith" and "to the best of his knowledge" applied the rules as they were written.
The report also said the persistent radio messages from Red Bull and Mercedes also contributed to Masi not being able to focus on his job.
"It was found that these communications were neither necessary nor helpful to the smooth running of the race," it said.
Mercedes boss Toto Wolff told the UK's Sky Sports F1 he was happy the FIA report was made public and brought closure to the 2021 season.
"They've been very transparent in making it public,' he said.
"It says human error, one rule was obviously not interpreted in the right way.
"But now we need to close the chapter."
