Rivals stop chasing me in some games

[nb12]

I noticed that in several games other cars are severely underperforming in the second half of the game. The case in point is Lava Land. But Snow Storm and Mountains too. Is it a bug or by design?

[Ryan Deluz]

Are you perhaps 1 lap behind the other cars? Make sure you stay on track and follow the direction of the compass in the bottom left corner. If you get too far off track, or skip a part of the track you need to go on, you can end up 1 lap behind. When you are far behind the other cars (even if you are "in front" but 1 lap behind) the other cars slow down substantially.