So what caused the accident, and who was at fault? We take a look at some of the themes that emerged as the debate continued after the race.
What are the safety car rules?
The rules that relate to the use of the safety car in F1 have been refined and developed for over 25 years.
The section of the 2020 sporting regulations that relates to restarts, and which was cited by the stewards when 12 drivers were given a warning on Sunday, is Article 39.13.
There are four phases to the restart notification process, as race director Michael Masi explained.
"The first phase is that we advise all teams through the messaging system, which is also what's seen on the graphics, that the safety car is in this lap," he said.
"So therefore that prepares all of the teams to advise their drivers accordingly.
"From there, the next point is that at a predetermined point at each circuit generally, the safety car boards are withdrawn, however the yellow flags continue to be displayed.
"Then once the safety car is clear of the circuit, the yellow flags are withdrawn and the green flag is displayed at the control line only. And that's really the phases of it."
When can drivers overtake again?
A critical requirement is that drivers can't overtake the safety car until it heads into the pit entry, which is officially marked by what is known as "Safety Car Line 1."
The rules note: "When the safety car is returning to the pits it may be overtaken by cars on the track once it has reached the first safety car line."
Until a few years ago, drivers could start racing and passing each other at that safety car line, in other words typically at the start of the pit entry.
However, that was changed to the control line, or the circuit's official timing point. So in effect it became a rolling start from the grid, rather than from just beyond the final corner as previously, but with no passing allowed until cars have crossed the line.
Masi made it clear after the race that, as is standard practice, the drivers were reminded in Mugello of their responsibilities.
"The drivers were all advised very clearly at the drivers' meeting on Friday night," he said. "There were two key parts to remind them.
"One was to ensure that they don't overtake the safety car before the safety car line at pit entry. The second part was, which is unusual for this circuit, is that the control line where they can overtake is located close to the pitlane exit."
Masi acknowledged that the long straight at Mugello and relatively late location of the control line played a role in the circumstances of the accident, in part because as leader Bottas knew that he would be vulnerable to being passed by Hamilton if his team mate got a good tow.
Taking off as late as possible reduced the possibility of that happening.
"We've seen similar matters in Baku," said Masi. "With such a long run, let's call it, to the control line, where the leader who has every right to dictate the pace has kept it quite slow to try and avoid a slipstream from the cars behind."
He added: "I think there was a combination of factors. But there was no doubt that the long straight adds to that. But the end of the day you race to the line. All the drivers are well and truly aware that there's no overtaking prior to the control line. And so it's not a new regulation."
Did the safety car lights go out too early?
One criticism that quickly emerged from the drivers, including race winner Lewis Hamilton, was that the safety car lights went out very late, giving the drivers little warning that the restart was about to happen.
"It's absolutely not Valtteri's fault at all," said Hamilton. "It's the decision makers. I don't know who. They're obviously trying to make it more exciting, but ultimately today you've seen they've put people at risk. So, perhaps they need to rethink that.
"They have been moving switching off the safety car lights later and later and later, and we're out there fighting for a position. Especially when you earn a position like Valtteri earned the position of being in the lead and then obviously they are trying to make it more exciting – but today was a little bit over the limit perhaps. But he did exactly what anyone would do."
However, the rules make no specific provision for how early or how late in the lap the lights should go out, and thus drivers are in essence expected to use their experience and make allowances for any circumstances.
Masi had no time for any suggestion from the drivers that the lights went out too late.
"Simply put, they can criticise all they want," said the Australian. "If we have a look at the distance perspective, from where the lights were extinguished to the control line, probably not dissimilar, if not longer, than a number of other venues.
"So, at the end of the day, the safety car lights go out where they do, the safety car is pitlane. We have the 20 best drivers in the world. And as we saw earlier today in the F3 race, those drivers in the junior category had a very, very similar restart to what was occurring in the F1 race, and navigated it quite well, without incident."
Was Bottas to blame for going so slow?
As is made clear in the regulations, the leader is entitled to set the pace, and decide when he wants to accelerate.
This was formally acknowledged by the FIA stewards on Sunday. In their decision to hand a warning to 12 drivers they noted that "the driver of Car 77 (Valtteri Bottas) and the other drivers involved in the restart not mentioned above complied with the regulations. Car 77 had the right under the regulations to dictate the pace."
Bottas stressed that he was only doing what any race leader would have done, and like Hamilton, he suggested that the lights had gone out late.
"We're allowed to race from the control line, which has been there for a while, I think," he said. "Just the difference this year has been the safety car, they are putting the lights off quite late, so you can only build the gap pretty late on.
"So, of course when you're in the lead you try to maximise your chances and I'm not at all to blame for that. Everyone can look at everything they want for it. I was doing consistent speed until I went. Yes, I went late, but we start racing from the control line, not before that.
"So the guys behind who crashed because of that, they can look in the mirror. There's no point whining about it. I don't know who's deciding what's happening with the safety cars but they're trying to make the show better by turning the lights later, so we can't build a gap early and then go like the corner before the race start."
Alex Albon, who was fourth in line, defended Bottas.
"I think when you put the control lines so far in front and then also leave the lights so late it's pretty obvious where Valtteri's going to take off," said the Red Bull driver.
"He's going to take off as late as he can, and I imagine the midfield know when Valtteri's going to go, and they are also trying to get a slingshot.
"And then when Valtteri doesn't go when they think he's going to go, that's when the concertina happens. It's dangerous but it's predictable as well in that sense because the closer you leave it or the less time you leave to let Valtteri decide when to take off, the shorter time he has to go so it's quite easy to read."
Why did the drivers get a warning?
Only three drivers were formally called to see the stewards after the race, namely Kevin Magnussen, Daniil Kvyat and Nicholas Latifi. However, when their decision emerged a total of 12 were named and given a warning
The stewards cited Article 39.13 and concluded "that the root cause of this incident was the inconsistent application of throttle and brake, from the final corner along the pit straight, by the above drivers.
"The stewards acknowledge the challenges the location of the control line presents at this circuit and the desire of drivers to take advantage of the restart.
"However this incident demonstrates the need for caution to be exercised in the restart situation and note that there was an extreme concertina effect which dramatically increased as it moved down the field."
They added: "We also note that some drivers might have avoided being involved in the incident had they not followed directly behind the car in front. By doing so they effectively blocked off all visibility of what was happening immediately in front of the preceding car."
The 12 drivers named were given the relatively meaningless penalty of a warning "as it is the view of the stewards that no one driver was wholly or predominantly to blame."
The only drivers to escape sanction were the leading trio of Bottas, Hamilton and Charles Leclerc, and the three who were at the very rear of the field, Romain Grosjean, Kimi Raikkonen and Sebastian Vettel.
From his vantage point Vettel made an interesting observation: "I was obviously I guess last at that point and behind Kimi, so it happened a bit further down the road.
"I didn't see exactly what led to it, but already even for me, it was a bit erratic in terms of speeding up, slowing down, speeding up, and then finally speeding up, and everyone was jumping on the brakes.
"There was a bit of a gap because Kimi was quite far behind the car in front, and probably it was better for the two of us."