Verstappen and Stroll made contact at Turn 1 late in the session. Verstappen had moved alongside Stroll on the run down to Turn 1 but Stroll had turned across the Red Bull as they reached the corner.
An expletive-laden Verstappen radio message was broadcast afterward, with the Dutchman saying: "Mate is this f------ guy blind? What the f--- is wrong with him?"
Both drivers were summoned to the stewards after the session to give their view on it. The stewards decided to take no further action as they felt neither driver was wholly to blame.
Speaking after the session, Verstappen said: "To be honest, I don't want to talk about it too much because I was so surprised.
"He just turned in while I was coming up to him. I don't know where I had to go.
"I was starting my lap, and he just finished his lap. We'll see what happens. It's FP2 [free practice two] and it's just a shame that we touch. It was very unnecessary."
Racing Point team boss Otmar Szafnauer said Verstappen was fully to blame for the collision.
"I can assure you 100% Max knew that Lance was there," Szafnauer told Sky Sports F1. "There's no way he doesn't know Lance is there. But Lance doesn't know Max is there. It's pretty simple to me."
Red Bull boss Christian Horner disagreed.
"You've got to go back to the previous lap," Horner said. "Lance has gone into the last corner and Max has let him go because he wants to get the tow.
"He's assuming that Lance is finishing a lap and he's not aware that Lance is going for a second lap, so he's let him past and he's tucked up behind him. He's taken the advantage of the tow, pulled up alongside him, and assumed he's going to back out of it because he knows he's up the inside.
"Obviously Lance, for whatever reason hasn't seen him, and he's committed to the corner and turned in. Both of them were probably expecting the other to back off. If that were a race, Max would have been deemed to be up the inside, therefore the car on the outside should have given way."