I've gathered all the parts of regulations concerned about the on-going controversy.
Here's what they say.
Art. 48.12 of the F1 Sporting Regulations
"*If the clerk of the course considers it safe to do so, and the message "LAPPED CARS MAY NOW OVERTAKE" has been sent to all Competitors via the official messaging system,* ***any*** *cars that have been lapped by the leader will be required to pass the cars on the lead lap and the safety car...*
*Unless the clerk of the course considers the presence of the safety car is still necessary,* ***once the last lapped car has passed the leader the safety car will return to the pits at the end of the FOLLOWING lap***. If the clerk of the course considers track conditions are unsuitable for overtaking the message "OVERTAKING WILL NOT BE PERMITTED" will be sent to all Competitors via the official messaging system."*
Art. 48.13 of the F1 Sporting Regulations
*"When the clerk of the course decides it is safe to call in the safety car the message "SAFETY CAR IN THIS LAP" will be sent to all Competitors via the official messaging system and the car's orange lights will be extinguished.* ***This will be the signal to the Competitors and drivers that it will be entering the pit lane at the end of THAT lap."***
Whilst Art. 15.3 of the F1 Sporting Regulations states:
*"The clerk of the course shall work in permanent consultation with the Race Director.* ***The Race Director shall have overriding authority in the following matters*** *and the clerk of the course may give orders in respect of them only with his express agreement:*
*a) The control of practice, sprint qualifying session and the race, adherence to the timetable and, if he deems it necessary, the making of any proposal to the stewards to modify the timetable in accordance with the Code or Sporting Regulations.*
*b) The stopping of any car in accordance with the Code or Sporting Regulations.*
*c) The stopping of practice, suspension of a sprint qualifying session or suspension of the race in accordance with the Sporting Regulations if he deems it unsafe to continue and ensuring that the correct restart procedure is carried out.*
*d) The starting procedure.*
*e)* ***The use of the safety car.****"*
​
The stewards, although they may only benefit from such a ruling, have determined that the Race Director is thence fully empowered to do what he did.
FOR THE 1ST MATTER (i. e. only some cars unlapped themselves) I add that Red Bull claim that 'any' in Art. 48.12 doesn't many 'all', so according to them it is at the discretion of the Race Director to choose which cars may unlap themselves.
FOR THE 2ND MATTER (i. e. SC withdrawn one lap too soon) I add that it has to be taken into account the possibility that 'overriding authority' (Art. 15.3) solely means that the Race Director may shorten or lengthen the period of a SC even if not in compliance with the clerk of the course, but, arguably, any such decision must still be in conformity with Art. 48.12.
Furthermore, [the stewards decided](https://www.fia.com/sites/default/files/decision-document/2021%20Abu%20Dhabi%20Grand%20Prix%20-%20Decision%20-%20Mercedes%20Protest%20Art.%2048.12.pdf) "*that* *notwithstanding Mercedes’ request that the Stewards remediate the matter by amending the classification to reflect the positions at the end of the penultimate lap, this is a step that the Stewards believe is effectively shortening the race retrospectively, and hence* ***not appropriate.***"
​
**My view** is that the stewards could only second Michael Masi's course of action, in spite of it being largely problematic at best. Mercedes would have expected that. What do you think, in light of the above?
PS: correct me if I've made any mistakes.