Six hours and 35 minutes into the World Endurance Championship's most prestigious race, the #83 Ferrari 499P driven by Kubica swerved into Vanthoor's #15 BMW M Hybrid V8 as they lapped the #92 Manthey Pure Rxcing GT3 entry on the approach to Mulsanne corner, which sent the Belgian driver into the wall and caused the BMW's retirement from the race.
The #83 Ferrari was given a 30-second stop-and-go penalty but managed to stay on the lead lap, which allowed it to remain in victory contention thanks to current safety car rules gathering all cars on the lead lap when the race is neutralised.
Vanthoor was furious with the stewards' decision and took to X (formerly Twitter) to express his discontent: "Thanks for all your messages, I’m okay! Just a small concussion! Just a bad day for our sport, pushing someone off at 300km/h and getting a 30-sec penalty. Sorry @FIAWEC, losing trust here."
Team boss Vosse told Autosport that it was intolerable that the Ferrari which had caused the crash was able to find its way back to the front of the pack, and said he would have advocated for a three-minute or five-minute penalty – which would have dropped the #83 car a lap down.
"At the end, it is something that we will not accept," the Belgian said. "For me, the penalty was very unfair. You take the race away from someone. You deserve to be somehow slowed down much more than being able to fight for the podium again three hours later."
However, Vosse has no hard feelings for Kubica, a former Team WRT driver who won the ELMS and WEC championships in the LMP2 class with the Belgian outfit in 2021 and 2023 respectively, while coming second at the Le Mans 24 Hours last year with team-mates Rui Andrade and Louis Deletraz.
"I'm close to Robert – he drove for us for a few years," Vosse pointed out. "We won the championship with him last year, and he's someone that I respect a lot.
"I will say that I did not expect something like that from him, but I will not judge him. First, I will cool down and speak to him probably next week about the incident.
"From a sportsman of his level – and he's really a sportsman, because I see him like that – I have to say, unfortunately, I've been disappointed about the situation."
The Le Mans 24 Hours has been disappointing overall for the BMW factory Hypercar squad, with Marco Wittmann spinning the same #15 car on lap six, while Robin Frijns crashed the #20 machine after bouncing off a kerb at the Ford chicane at 6:23pm.
The car limped to the pits and went back on track only 21 hours later to see the chequered flag, without being classified.
Andreas Roos, head of BMW M Motorsport, explained to Autosport that the car could have been back on track earlier but the German constructor didn't want to risk further damage ahead of the Sao Paulo WEC round on 14 July.
"Le Mans can always be quite brutal," Roos added. "First thing is you shouldn't do any mistakes, which we didn't manage. Too many mistakes happening."
"That's how you try to win races today," Vosse analysed. "Unfortunately, we saw that we were quick at some stage, but maybe a little bit too quick, or trying too hard.
"We did not learn as much as we had hoped to about our cars, because at the end, we could not go through the night with our cars. Let's say that we have learned what not to do next year."
Addtional reporting by Heiko Stritzke and Rachit Thukral
