Hamilton's penalty compounds a miserable Saturday in Zandvoort for the seven-time world champion, who suffered a shock Q2 exit not long after his impeding offence.
It seems that in the Hamilton-Perez case, the stewards did not agree with the Brit's initial assessment, where he claimed over team radio that he was well out of the way of Perez.
The stewards reported that having heard the evidence from both teams, "when Car 11 [Perez] arrived, Car 44 [Hamilton] had already entered Turn 9 and drove back towards the racing line at the exit of Turn 9, thereby clearly impeding Car 11.
"Whilst there has been appropriate warning by the team and albeit the driver tried to move out of the way, he could have slowed down more in order not to impede the other car and therefore consider the impeding to be unnecessary in the sense of the regulations.
"Therefore a grid drop is applied in line with previous decisions," the stewards concluded.
Perez's immediate reaction was less calm: "What the f*** is this idiot doing?" he asked over team radio.
When back in the garage having made it into Q2 - though minus a fresh set of tyres having abandoned the initial lap - the 34-year-old was still unhappy.
"Yeah but we f****** waste a set so please, for worse than that I’ve been penalised so I don’t expect any less," he added on radio.
He was more rational in his post-race interview with Sky Sports F1, admitting it was unfortunate timing for Hamilton, though mentioned that the stewards had typically come down hard on these sorts of incidents.
"I think it will cost him a penalty but other than that I think it was just wrong timing wrong moment," the Red Bull driver added.
Indeed, Hamilton received nothing less than a three-place drop, and faces an uphill task to continue his rich vein of form.