Well, no explanation is needed frankly, but in Solo Race mode on the Barcelona track, the car Lamborghini Centenario (played by computer) at times comes first and completes the mission in under 8 secs. Is this a bug?
I would guess it's the result of a hack/exploit.
In a lot of online games with leaderboards, at some point in the games life some hackers figure out how to submit times without it being checked by the game.
So you start seeing times that are 0.001s for a race that is at least a minute. Or for high score things, a score of 999999999 (they basically can throw in any score they want).
They can post impossible scores because, and at that point I do not know exactly how, they can just tell the server 'Yes, I did x race in 0.001s' and the server just takes it like it's any other score.
Back to the original point: Probably the game takes the general leaderboards of the race and gives you a time that would be the average for the top 10% of racers, then the top 20, 30, 40, 50 for the times of your opponents. Thing is, a bunch of people clock in those hacked times of 0.001s, pulling down the average of the 'top 10% of players' to something like 8s.
I don't know the game in general, but if you look at the leaderboards of all players on that race, I would guess you would see a bunch of 0.01s at the top of the leaderboards.