nzkc:

 

How did Norris avoid a penalty for the start!? Unlike the F1TV commentators I thought he had stopped before the lights changed but I think he was then outside his start box. Very lucky there. But then was a bit unlucky with the pit stops having to stay out to avoid sitting double stacked.

 

From the Stewards:

 

The Stewards reviewed positioning/marshalling system data, video and determined that the video appeared to show that Car 4 moved before the start signal was given. However, the FIA approved and supplied transponder fitted on the car did not indicate a jump start.

 

Article 48.1 a) of the Formula One Sporting Regulations states clearly that the judgment of whether or not there was a jump start is to be made in accordance with the transponder, which did not show a jump start. In the  circumstances, we took no further action.

 

Basically a 'computer said no' situation. Saw comments elsewhere this has happened a few times, the transponder has (potentially not) picked up on something not visible in the video recordings which pushes towards declaring it was a legit start.