The McLaren driver was around five seconds behind race-leader Max Verstappen early in the race when the VSC was called out because of debris on the track after Perez had collided with Haas driver Kevin Magnussen.
As Norris approached Spoon Curve, he closed in on the very slow Perez, who was returning the pits to get his car repaired.
However, unsure about whether or not Perez had a problem, he had to back off to avoid the risk of getting a penalty for overtaking the Red Bull under the VSC.
That allowed Verstappen to pull out a further five-seconds advantage, which made the Dutchman’s life easier at the front of the pack.
Norris said that, amid uncertainty about what Perez was up to, he could not risk the pass – so had to slow and see valuable seconds slip away.
Asked by Mototsport.com what happened at that moment, Norris said: “I don't know what… he must have had a problem, right?
"But the thing is you can't overtake under the VSC unless it’s obvious the guy has a problem. I didn't know if he had a problem, or whether he was just backing me up. I didn't know and I couldn't take the risk of just overtaking him.
“He was going so slowly and then when we get the flashing dash for the VSC ending, he went into first gear and then I was on the outside of him because he was going so slowly, and then he almost crashed into me. So, I honestly have no idea.
“I was shouting in my helmet. I was swearing quite a bit, but I was so confused. I didn't know what I could do. I'm losing time to Max. The Ferrari guys were, I think, 1.4 seconds behind me after being I think 12s or 13s, so I lost 10 seconds. And I didn't know what I could do at the time.”
Norris thinks that if Perez had been limping back to the pits, then he should have made it more obvious to get out of the way.
“If he has a problem, he should pull over and make it obvious that he has a problem,” added Norris. “He didn't and therefore I couldn’t take the risk of passing under a VSC, so no idea.
“I don't think it would have changed the world, it just made me stress for a little bit more. But it would have been maybe just a bit better to put Max under a little bit of pressure at least, after that. I don't think we would have been quite as far behind.
“It was a frustrating time, but maybe I'll ask next time what you're allowed to do. I think I did the right thing, so all okay.”
McLaren team principal Andrea Stella said the situation was very tricky to understand at the time, because there was always the potential for a slow driver ahead to trick a rival into overtaking him.
“It doesn't affect the final result, but it's a bit inconvenient and it's tricky,” he said. “It's tricky because, as a driver, you can only judge based on the reference time, and Lando could see that he was losing quite a lot of time compared to the reference time.
“But it's always a little discretional. Maybe the driver that is holding you could take an unsportsmanlike penalty, but you could also be summoned because you overtook.
“We played very cautiously. We thought let's wait, let's ask, but this takes time and we lost some time.”
