From motorsport.com
https://www.motorsport.com/indycar/news/penske-newgarden-loses-st-petersburg-indycar-race/10602791/
Penske violated two of the following rules:
Rule 14.19.15. An indicator to enable Push to Pass will be sent via CAN communication from the timing and scoring beacon on board the Car to the team data logger. This signal must be passed on to the ECU unmodified and uninterrupted during all Road and Street Course Events.
Rule 14.19.16. Race Starts and any Race Restart that occurs before the lap prior to the white flag or prior to three minutes remaining in a timed Race Event will have the Push to Pass system disabled and will be enabled for a given Car once that Car reaches the alternate Start/Finish line.
Per the rulebook, the violation is considered a Race Procedure Penalty (9.2.2.), which includes the right to reposition the driver and car in the postings or results, with a disqualification (9.2.2.6) that includes the forfeit of points and awards.