F1 CEO and president Stefano Domenicali held his regular Saturday coffee meeting with team principals in Montreal, during which there were clashes between bosses over porpoising in the wake of the FIA's technical directive.
Mercedes F1 boss Toto Wolff said after the meeting that the behaviour of his rival team bosses amid the porpoising debate has been "pitiful" and "disingenuous", playing political games while he stressed the safety concerns involved in the matter.
Rival teams have been less vocal than Mercedes about any potential FIA intervention, particularly Red Bull, which has not struggled so much with porpoising on its car this year.
As conversation turned to the porpoising issue in the meeting, it was pointed out to Wolff that some teams - especially Ferrari and Alpine - felt the TD was a breach of the regulations and his team running a second floor stay was illegal.
It is understood that Horner then suggested to Wolff that Mercedes' porpoising problems lay with the concept of the team's car, rather than the regulations themselves, and that it was up to the German manufacturer to get its own house in order.
The meeting was held with the cameras from Netflix present amid their filming of the fifth season of Drive to Survive, as they followed Wolff during the Montreal weekend.
Asked by Motorsport.com if it was a good thing to have Netflix filming a private meeting, Horner replied: "I think there was an element of theatre going on in that meeting.
"So you know, maybe with Lewis's new movie coming along, [they're] getting him enrolled for it."
Aston Martin team boss Mike Krack said the meeting proved to be "a bit emotional for some" as tensions ran high during the debate.
Mercedes fitted a second stay to its W13 car to aid with porpoising in Friday practice in the wake of the technical directive being issued by the FIA, only for it to be removed ahead of FP3.
Other teams had questioned whether it was within the regulations, putting Mercedes at risk of facing a protest.
There was also some concern from teams about the timing of its introduction, given the FIA had only sent the technical directive out when they were travelling to Montreal.
Horner felt the porpoising issue was always going to be most severe in Azerbaijan and Canada, but that it "didn't look like an issue in the race".
"There is a process of these things to be introduced," Horner said.
"I think what was particularly disappointing was the second stay, because it has to be discussed in a technical forum. And that is overtly biased to sorting one team's problems out, which was the only team that turned up here with it even in advance of the TD.
"So work that one out."
