On the cooldown lap after the finish a significant number of spectators made it onto the course before all cars had made it back to parc ferme.
Autosport understands that, as it's not the first time a similar incident has happened at Montreal's Circuit Gilles Villeneuve, the FIA decided to firm up its response by formally summoning the Canadian promoters, the Octane Racing Group, over the recurring issue.
Watch: Canadian GP Race Review - Wet and Wild Vs Cool and Calm
After investigating the incident, the stewards found the local promoter in breach of article 12.2.1.h of the International Sporting Code, noting a "failure to take reasonable measures, thus resulting in an unsafe situation".
They judged that based on video evidence "the security measures and/or security officers and/or equipment which were expected to be in place for the event were not either enforced or were not sufficient resulting in an unsafe environment for the spectators and drivers."
In the stewards’ hearing the promoter admitted that the event's security precautions were not robust enough to prevent an early track invasion, despite allocating more resources to it, and agreed the situation was not acceptable and would be investigated thoroughly.
The stewards decided that the promoter must present a formal remediation plan to the FIA by 30 September that will lay out how the situation will be prevented from happening again.
They also urged the FIA to look into the matter as it relates to a serious issue around safety and security, and warned another repeat would be met with a significant financial penalty.
Early track invasions are not uncommon, with the Australian Grand Prix promoters also pulled up over similar problems at the 2023 edition of the Melbourne race.
In addition to spectators invading the track while cars were still running, some fans also reached the stranded Haas of Nico Hulkenberg.
In response the post-race Australian GP track invasion was banned for 2024, marking a temporary end to a long-standing Melbourne tradition.
A similar situation also occurred at the 2023 Brazilian Grand Prix, where fans broke onto the track at Turn 1 as the cars took the chequered flag.
Canada's entertaining wet-to-dry race was won by Red Bull's Max Verstappen, who defeated McLaren driver Lando Norris and Mercedes' polesitter George Russell.
The Montreal race was attended by a record number of 350,000 spectators across the four-day event, up from 345,000 in 2023, and was plagued by several other logistical issues on the cramped environment of the man-made island that houses the semi-permanent circuit.