Race director Masi was involved in controversial decisions at the final race of last seasonThe FIA says it knows about radio messages from the Abu Dhabi Grand Prix that have raised fresh questions about last year's title-decider.
The messages seem to be further evidence of race director Michael Masi reacting to Red Bull's suggestions as to how to end a safety-car period.
And Masi echoes Red Bull's language in a response he gives to Mercedes.
A spokesman for Formula 1's governing body said: "We are aware of this and it is part of the investigation."
In the radio messages, Red Bull sporting director Jonathan Wheatley is heard advising Masi on how to deal with lapped cars that are on track between the leaders as he attempts to organise a restart before the laps run out.
At the time, Red Bull's Max Verstappen was on new tyres behind Mercedes driver Lewis Hamilton on old rubber, which meant that if the race was resumed Verstappen would have a huge advantage and would likely win the race and championship.
Wheatley says: "Those lapped cars; you don't need to let them go right the way around and catch up with the back of the pack. You only need to let them go, and then we've got a motor race on our hands."
Masi replies: "Understood."
After the race, Mercedes team principal Toto Wolff gets on the radio to tell Masi that what he has done is "not right".
Masi replies: "Toto, it's called a motor race, OK?"
The radio transmissions are not new - they were on a video released by Formula 1 on 16 December, four days after the race - but the one from Wheatley appears to have missed general circulation in the storm that followed.
Their emergence into the public arena - they were trending on Twitter on Wednesday with the hashtag #F1xed - has come days before the FIA is due to reveal the outcome of its inquiry into Abu Dhabi to a meeting of the F1 Commission next Monday.
And it fits an impression of Masi acting in Red Bull's favour during the race and against Mercedes' interests.
Red Bull team principal Christian Horner had previously said to Masi: "Why aren't we getting these lapped cars out of the way? You only need one racing lap."
It is widely acknowledged within F1 that Masi failed to follow the rules correctly in Abu Dhabi, and that in doing so he had a direct effect on the outcome of the world championship.
The FIA inquiry was set up to analyse how the mistakes at Abu Dhabi were made, and to put in place protocols to try to prevent them happening again.
The FIA has access to all team radio from Abu Dhabi for the inquiry they are conducting into the race.
And the outcome could have significant consequences - Hamilton, who lost the championship in the controversial ending of the race, will not decide whether to return to F1 this year until he has seen the results of the FIA inquiry.
Race director Michael Masi's failure to apply the rules correctly allowed Max Verstappen to overtake Lewis Hamilton on the last lap of the last race of 2021What happened in Abu Dhabi?
Hamilton had led the race from the start until a safety car period with five laps to go.
Masi then failed to follow the rules correctly in at least two ways - to do with lapped cars and the timing of the restart.
Masi's position and actions are at the centre of the FIA inquiry, with many F1 insiders believing his position is untenable following his errors in Abu Dhabi - and further controversies at previous races.
FIA head of single seaters Peter Bayer, who is leading the inquiry, has hinted that Masi will not remain as race director in 2022.
When the race was restarted, Hamilton - on old tyres - was passed by title rival Max Verstappen's Red Bull - on fresh ones - and the championship changed hands.
The race director has discretion as to whether lapped cars are let through to unlap themselves - but the rules state that "any cars that have been lapped by the leader will be required to pass the cars on the lead lap and the safety car".
Masi ordered only the cars between Hamilton and Verstappen to overtake but left any between the rest of the top six where they were.
In addition to that, the rules dictate that once the lapped cars are let through, the racing will start "at the end of the following lap", whereas Masi restarted the race immediately.
Mercedes appealed against the result of the race in Abu Dhabi, but the stewards rejected their appeal on the grounds that a subsequent article in the rules states that once the message "safety car in this lap" has been displayed, the race director is obligated to start the race at the start of the next lap.
But many senior figures accept that the two articles in question - 48.12 and 48.13 of the sporting regulations - are intended to work in tandem. In other words, the lapped cars are to be let through, and the message about the safety car coming in displayed during the following lap - not that one supersedes the other, as the stewards argued.
It is believed Masi took the decisions he did because he was trying to accede to an agreement made with the teams that races should not finish under the safety car if at all possible.
