Max Verstappen, Charles Leclerc and Lewis Hamilton have to go to the stewards in Austria. They would not have followed the instructions concerning the parc fermé.
It is now clear that the offences do not appear to be very serious. The drivers' physios are not yet allowed to come close to the drivers in the parc fermé. That is only allowed after the race in the cooldown room. This rule has been violated.
It is likely that the drivers will be fined.