The Aston Martin driver was reported for making "more than one change of direction to defend a position" while battling with Valtteri Bottas.
After an investigation he received a five-second penalty and a penalty point on his FIA superlicence. The penalty did not change his finishing position of 12th place.
Race control also looked at Stroll's move to pass Bottas when the virtual safety car period ended, when it was suggested that he'd forced the Alfa driver off the road, but no action was taken on the incident.
Earlier in the weekend he received a three-place grid penalty and two penalty points following a collision with Nicholas Latifi in qualifying, although his starting position was not impacted as he hadn't set a lap time.
In the summary of the weaving incident the stewards made it clear that Stroll had made more than the permitted single move: "On the main straight, Car 18 [Stroll] was ahead of Car 77 [Bottas]. Stroll moved right to defend against a potential overtake from Bottas.
"Stroll returned to the racing line and then moved to the right for a second time to defend from another move by Bottas. The second move breaches the regulation which prohibits more than one change of direction to defend a position."
Stroll made it clear that he didn't understand why he was penalised.
"I don't get it," he said when asked about the incident by Motorsport.com. "It was two guys weaving all the time, it's just the last move really.
"You can weave down the straight as long as you don't weave when the guy's approaching very close behind you. I'm weaving to try and break the slipstream, not to try and defend, and then they penalise me for it. I don't get it.
"I guess a lot of funny decisions going on right now."
Regarding his opportunistic move on Bottas he said: "On the edge, yeah. He was sleeping on the restart, the virtual safety car restart, so I caught him sleeping. I thought that was good racing.
"The penalty, I mean it's annoying to get penalised, because I don't really understand their reasoning behind it, but it didn't change our final position because we had more than five seconds to the car in P13 or whatever.
"It's always nice to be fighting in the quicker car that's attacking rather than defending, but we tried our best, just didn't really have the pace to pick up points."
Stroll has now picked up eight penalty points within a 12-month period.
Asked about the risk of a race ban, his team boss Mike Krack acknowledged that the new race directors Niels Wittich and Eduardo Freitas have a strict approach.
"I think we need to learn how the new race directors and how they govern it," said the Luxembourger. "We learned a little bit in the hard way at the moment.
"We will keep it under control. I mean, we had two points yesterday, we had one point today. Obviously when the car is not as it as you want it, then the drivers try as much as possible to defend.
"I think it's a combination of [that and] maybe new ways of governance, but that would be too easy to say. I think if we had a better car we will not have these issues."
