Formula 1 race director Michael Masi says he investigated a possible jumped start by Valtteri Bottas in the Hungarian Grand Prix, but confirmed the Mercedes driver was within FIA tolerances.
Bottas edged forward at the start before stopping and going again when distracted by a light on his dashboard, co-incidentally leading Vettel to tell his Ferrari team that Bottas had jumped the start.
Video evidence appeared to confirm that, but the key to an official transgression is the detection system that is built into the track.
"There are two parts to that," Masi explained.
"The means by which a false start is determined is actually clearly determined in the sporting regulations, and has been the same process for a number of years, which is the transponder that's fitted to each car is the judgement mechanism.
"There is a sensor in the road, in the track, as well.
"There's a tolerance within that, and as we saw in Japan last year [when Sebastian Vettel did something similar], that is the determining factor.
"So there was nothing further to have a look at. We spoke to the timekeepers immediately, and they reviewed all the data, and that was the end of the matter."
While Bottas escaped sanction, Haas drivers Kevin Magnussen and Romain Grosjean both received 10-second penalties for receiving radio messages telling them to pit on the formation lap, a move that saw both men climb the order in the opening laps.
"There was a technical directive that came out in 2017, clarifying what communications the team cab make to the drivers on the formation lap, which relates to Article 27.1 of the sporting regulations, which is that the driver must drive the car alone, and unaided," Masi added.
"Part of that summons is that both drivers were called in by their engineers to change tyres on the formation lap, which is not permitted within that technical directive that was issued at the time about what can and can't [be said].
"In essential terms the only communication that can be made with the driver during the formation lap is to do with safety matters, so if it's an issue of imminent safety, then that communication can take place."
Finally Red Bull Racing was investigated for the unusual offence of drying Alex Albon's grid spot with blowers, something that Masi had specifically cautioned against in notes sent to teams just before the start.
However after reviewing the evidence, the stewards took no action.