Lewis Hamilton and Mercedes face a stewards' investigation for a DRS infringement on the seven-time F1 champion's W12.
A report from FIA technical delegate Jo Bauer following qualifying for the São Paulo Grand Prix reads: "The uppermost rear-wing element adjustable positions were checked on car number 44 [Hamilton] for compliance with Article 3.6.3 of the 2021 Formula One Technical Regulations.
"The requirement for the minimum distance was fulfilled. But the requirement for the maximum of 85mm, when the DRS system is deployed and tested in accordance with TD/011-19, were not fulfilled.
"I am referring this matter to the stewards for their consideration."
Hamilton comfortably qualified fastest ahead of Saturday's sprint race, finishing with a leading time of one minute 07.934secs, almost half-a-second quicker than Red Bull's Max Verstappen who joins the Briton on the front row.
Hamilton was aided by a new internal combustion engine that gave him a power boost, although faces a five-place grid penalty for Sunday's grand prix.
If Mercedes is found guilty of a technical infringement, however, the potential knock-on effect is that Hamilton is disqualified from qualifying.
That would place Hamilton on the back row for the sprint from where he would likely struggle to make it into the top 10.
In addition to the five-place penalty for the grand prix, Hamilton would certainly start Sunday's race towards the rear of the grid again.
Should Verstappen win the grand prix, or at least finish on the podium, he would open up a significant cushion over Hamilton in the drivers' standings going into the final three races.
The Dutchman already has a 19-point cushion going into the races this weekend.