No Penalty for Norris Stop

Did ya'll see Lando Norris stop in the pit right before entering the track? Not only did it blow the race for Lando, but they could have incurred a monetary penalty. Luckily they did not- because the FIA could not determine there was something wrong with the car when it left... which is strange because why would they stop him and roll him back if just for 'caution' ?
https://mclarenchat.com/forum/news/973

 

incident at 2:35