The FIA says the quick change of start lights at the French Grand Prix should not have caught Formula 1 drivers by surprise because it was within its permitted tolerances.
Sebastian Vettel was among a handful of drivers to admit after the race he was "a bit surprised" by how quickly the lights went out, and did not think he was the "only one that probably reacted a little bit late".
The lights were held for around 0.8 seconds, which race director Michael Masi said was in line with what the rules allow.
"The sequence was fine," said Masi. "It was all within the boundaries.
"I think a couple of drivers said it was a bit quick, but it was certainly within the tolerances that we have."
F1's race start sequence is controlled by permanent starter Christian Bryll, who took over that role at the Bahrain GP when the duties of former F1 race director Charlie Whiting were split between Masi and himself.
But Bryll has no restriction on the timing of when he decides the lights go off, as F1's regulations over the start procedure are open-ended on this front.
Article 36.9 of F1's sporting regulations states: "Once all the cars have come to a halt, the five second-light will appear followed by the four, three, two and one second lights.
"At any time after the one‐second light appears, the race will be started by extinguishing all red lights."
Asked about driver complaints that the lights were out too quickly, Masi said: "It may have been from their perspective but an actual time of within the regulations, they were well and truly within the boundaries."