The German had posted a time good enough to join Max Verstappen on the front row of the grid in Q3, seconds before the red flag was issued by the stewards following Oscar Piastri's crash on the exit of Turn 7.
Following the clean-up operation of the Australian's stranded McLaren, the session resumed but in far worse conditions than those that had preceded the short hiatus.
This cemented Hulkenberg's provisional position on the front row, as Fernando Alonso was unable to complete his time as he was in contention to join Verstappen on the front row.
According to a document circulated by the FIA after the conclusion of the session, Hulkenberg had earned a summon to the stewards' room for an "alleged breach of Article 37.6 a) of the FIA Formula One Sporting Regulations - Car 27 failing to stay above the minimum time set by the FIA ECU at 16:59."
There is a minimum time required for the drivers to return to the pitlane following a red flag, and the stewards have felt that Hulkenberg allegedly went too slowly against the mandated delta time which has warranted an investigation.
More to follow
Source: Autosport