Luca Ghiotto has lost his second place finish at the Monaco Feature Race on Friday afternoon.
The UNI-Virtuosi driver crossed the line behind Nyck de Vries, who took his second consecutive win in the FIA Formula 2 series.
However following the race, it was "discovered during Parc Fermé checks that the car of Luca Ghiotto was using rack stops of a thickness that did not comply with Article 2 of the 2019 FIA Formula 2 Championship Technical Regulations and Page 75 of the Dallara User Manual".
As a result of the disqualification, Sergio Sette Camara has been promoted to third place, and Nobuharu Matsushita inherits second. Ghiotto will start Saturday's Sprint Race from the back of the grid.
Mahaveer Raghunathan also received a penalty for hitting the rear of Jack Aitken towards the end of the 41 lap race.
Aitken was pitched into the barriers by Raghunathan at the Turn 6 hairpin, putting him out of the race with damage.
Raghunathan, who was originally classed as 15th in the final standings, received a drive-through penalty that has been converted into a 20 second time penalty for causing an avoidable accident.
There was also some confusion after the race start when a number of cars were placed a lap down.
The stewards found that the restart procedure was not followed correctly when the cars emerged from the pit lane following the red flag, which put 11 drivers one lap down.
“The protest is well founded and the protester did not act in bad faith,” read a statement. "The protest deposit is returned to the competitor and the stewards take no further action.
“Upon receipt of the protest, the stewards investigated the matter in depth with the race director, race control personnel and timing personnel. In the course of this investigation it was revealed that race one was suspended with a red flag that was not preceded by a safety car.
"The cars were subsequently correctly assembled in the pit lane under Article 41.3 of the aforementioned sporting regulations.
“In preparation for the restart, the cars were properly re-ordered in the pit lane in the order they crossed the last timing loop prior to the red flag period. A decision was subsequently made not to further adjust the restart order.
"Article 42.3 of the 2019 FIA F2 Sporting Regulations specifies the manner in which the restart order is to be re-established at the restart.
"That process was not executed in that those cars originally in pit lane ahead of the leader as well as lapped cars were not allowed to transit the course and join the restart order at the rear.
"While this procedure negatively impacted the remainder of the race by putting significantly more cars down a lap than would otherwise have been the case, the Stewards find no equitable method to resolve this error and accordingly leave the results from Race 1 as they stand."