Nico Hulkenberg, Lance Stroll and Carlos Sainz have been reprimanded - but escaped grid penalties - for their roles in the farcical end to Italian GP qualifying.
The three drivers were found by stewards to have driven 'unnecessarily slowly' at the start of the out-laps in Q3 and therefore played a "significant role in the banking up of cars at a critical stage" of qualifying.
Stewards added they "strongly recommend that the FIA expedite a solution to this type of situation" to avoid a repeat of the bizarre scenes at the end of qualifying when eight drivers missed out on a final lap time.
F1's qualy chaos: What has been said?
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In a separate but related investigation, stewards took no action against Hulkenberg for the Renault driver going straight on through Monza's first chicane when he initially took to the track from the pit lane.
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'One of the silliest things I've ever seen in F1'
Monza qualifying - and Charles Leclerc's narrow pole victory for Ferrari over Lewis Hamilton - were overshadowed by the bizarre events on the final out lap of Q3.
After their first laps in the final shootout and Kimi Raikkonen's crash, drivers were waiting as long as possible in the pits before heading out again - looking to utilise the slipstream at high-speed Monza - but only Sainz and Leclerc, who had provisional pole, managed to get around to start their last laps.
Hulkenberg was the first driver out of the pits with less than two minutes remaining in qualifying, ahead of Stroll, Sainz and the Ferraris. But the Renault driver went straight on through the bollards at the Turn One chicane.
Stroll then slowed down to let Sainz through and the McLaren was then side-by-side with the returning Hulkenberg, effectively blocking the track for those behind him.
He eventually sped up to lead the field but with time running out, all drivers were effectively racing each other for track position, and to make the line before the end of the session.
With seven drivers timed out of the session as a result - including Sebastian Vettel and both Mercedes cars - Sky F1's Martin Brundle described it as "one of the silliest things I've ever seen in F1".
Renault's Daniel Ricciardo, caught up in the chaos, said: "Everyone was just trying to get a bit too clever and it just encouraged everyone to create a mess."
Mercedes boss Toto Wolff, meanwhile, described the actions of some drivers as "just junior class".
Hulkenberg escapes chicane sanction
The Renault driver had initially been called to the stewards after qualifying to explain why he had left the track at the chicane at the start of his final out lap.
After reviewing video and GPS evidence, stewards said it was not clear Hulkenberg had 'deliberately' left the circuit to gain an advantage.
'The driver stated that he was focusing his attention on the cars that were behind him and that he left it too late to turn the corner so he went straight ahead into the chicane,' read the verdict.
'The stewards noted that he entered the corner at the same speed as he did on his previous fast lap. He was also in third gear instead of second gear which he used on his previous out lap.
'The Stewards note that the regulation refers to "deliberately" leaving the track and in his case we are unable to determine that the driver deliberately left the track.'
Meanwhile, in a further stewards' investigation on Saturday night at Monza, stewards ruled no action was required against Vettel over a charge of leaving the track and gaining an advantage at the Parabolica.
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