Max Verstappen has continued in largely excellent form since then, though wins for both drivers at McLaren, Ferrari, and Mercedes have demonstrated how Red Bull's advantage has slimmed, if not evaporated entirely.
One reporter has suggested that an order to remove a 'clever' design element on their cars could have hampered the team, but a Red Bull representative has forcefully denied that is the case.
Why are Red Bull no longer the outright fastest car?
Red Bull have dominated the 'ground effect' era of F1 since 2022, winning both drivers' and constructors' championships in both full seasons since the regulations changes.
This year, Verstappen looks to have his fourth title under control, but their advantage as a team is just 42 points over McLaren.
Red Bull's gap to the other teams seemed relatively steady until the Miami Grand Prix, which Lando Norris won.
Including that race, Red Bull have only won three times in the last nine events, despite Verstappen's only blemish of the opening five races being his mechanical failure in Australia.
Now, F1 reporter Peter Windsor has written that Red Bull were ordered to remove a design feature before the Florida race.
On X, he said: "Looks as though RBR [Red Bull Racing] might have been running a clever rear cross-brake inertia valve before they were obliged to remove it before Miami.
"This could explain Max's RR [rear right] brake drama in MEL [Melbourne, where he retired with his rear right brake smoking] and his turn-in grief since China."
Verstappen has been vocal on team radio complaining about issues with the car's balance and steering, especially so as wins have dried up for the triple world champion.
In Hungary, the Dutchman complained that, "I’m minus five brake bias and the thing just doesn’t f****** turn. It’s unbelievable.”
Red Bull's supposed 'cross-brake inertia valve' could have allowed asymmetric braking, something the sport's governing body, the FIA, have made clear is prohibited in the latest changes to the sporting regulations.
Whether Red Bull were benefitting from such a piece of engineering is unclear. Calum Nicholas, a mechanic who has been with Red Bull since 2015, disputed the claim that the team had been ordered to remove any such valve.
"Yea… this is bulls***…. Unsurprisingly," he replied in response to Windsor's post. When pushed on why he believes that is the case, Nicholas added: "I’ve been building the car for the last 14 races."
Nicholas is one of the more prominent engineers on the grid due his social media presence, often engaging with fans on F1 and non-sport matters.