The contrast to the outcome of a very similar incident in Canada two races ago between Mercedes' George Russell and Verstappen was notable.
In Montreal, after the stewards took no action, Red Bull lodged a protest, but it was dismissed out of hand.
Piastri said: "Going back to Canada, I think he had to evade more there than he did today. So, yeah, I'm a bit confused to say the least."
There was also the feeling within McLaren that Verstappen may have 'gamed' the system by exaggerating how much it affected him.
"I don't think he had to evade me," Piastri said. "He managed the first time."
Team principal Andrea Stella said: "We'll have to see also if other competitors kind of made the situation look worse than what it is.
"Because we know that as part of the race-craft, some competitors definitely have the ability to make others look like they are causing severe infringement when they are not."
Verstappen said: "The thing is that it happened to me now a few times, this kind of scenario. I just find it strange that suddenly now Oscar is the first one to receive 10 seconds first."
Was that because because there was no difference from what Russell did in Canada?
"Well, to the stewards, yes, (there was)," Verstappen said.
The end result was that Norris has moved himself on to four wins for the season, one short of Piastri.
"I felt like I drove a really strong race," Piastri said. "Ultimately, when you don't get the result you think you deserve, it hurts, especially when it's not in your control.
"I will use the frustration to make sure I win some more races later."
Both have two weekends off to reset and refresh before battle recommences at the Belgian Grand Prix, the start of the second half of the season.