Seems as though it was fucked, just like we all thought.
In a release sent out by IMSA late Monday, the error was explained:
Due to an officiating error in race control, IMSA inadvertently announced and subsequently displayed the white flag with under three minutes remaining in the race. At the end of the lap, the race-leading No. 7 GTP car then received the checkered flag with 1 minute, 35.277 seconds still remaining, ending the race short of the planned 24 hours by effectively one lap.
Based on Article 49 of the 2024 IMSA Sporting Regulations and Standard Supplementary Regulations, should the checkered flag be inadvertently or otherwise displayed before the leading car completes the scheduled number of laps or before the prescribed time has been completed, the race is nevertheless deemed ended when the flag is displayed.
https://www.autoweek.com/racing/more-racing/a46575517/inadvertent-checkered-flag-ends-rolex-24-early/