Ferrari boss Fred Vasseur said the sudden departure of Formula One race director Nils Wittich was strange ahead of title-deciding grands prix.
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Both championships are still to be won, with Red Bull's Max Verstappen on the brink of clinching his fourth in a row but the constructors' battle more open between leaders McLaren and Ferrari.
Wittich's departure, with immediate effect, was announced last week with plenty of speculation but little explanation of why he left.
Drivers had expressed their surprise at the move on Wednesday.
"The momentum of this decision is a bit of an odd topic for me because now we are at the end of the championship, it's probably the three most difficult races to manage," Vasseur told reporters at the Las Vegas Grand Prix on Thursday.
"Vegas, if you remember last year, Qatar, and Abu Dhabi, the last one of the championship. The momentum is strange for this, for me.
"But I'm not behind the scene on the discussion into the FIA, and so that means I don't want to make any position on this, but the momentum is strange."
Mercedes team boss Toto Wolff, who saw Lewis Hamilton lose a championship in Abu Dhabi in 2021 after then-race director Michael Masi changed safety car procedures, said stability was needed.
Alpine's Oliver Oakes said new race director Rui Marques, who has been promoted from F2, was well qualified for the Formula One role.
"I think he'll be fine. I think at the end of the day, if they've given him the chance, it's because everybody thinks he's ready to step up and take that position," said the Briton, who knows Marques well from running teams in the junior series.
Sky Sports television commentator and former racer Martin Brundle told viewers it was "very difficult to rationalise" the situation.
"Niels Wittich, we are reading, said, 'I was fired, I didn't step away from it'. He looked like he was enjoying it, I think he fully expected to be here," he added.
Wittich was quoted by German website motorsport-magazin.com as saying he had not resigned, without giving further details.
The FIA had said he had left "to pursue new opportunities".
"Until we understand more about it and why, whatever they were dissatisfied with, it's very difficult to comment on whether it was a good or a bad decision," Brundle added.
"But coming into what is a very difficult race here, it's absolutely not optimal. Surely you'd have waited until the winter?"