I tried to do the quest "Spikeball" (this quest is in Reaper's March, at Hadran's Caravan), but the quest seems to be broken, the NPCs leave the racetrack right before the bridge, then they come back on it, but get despawned right before the cave part. Before I could reach the finish line, they get spawned there, with a notification: "Failed: Opponent Wins". I did a recording of the issue:
I did the race twice in this video, on the first try I let them take the lead to show how they leave the track, and where they disappear. On the second try I took the lead, none of them ran past me, but they still get spawned at the start/finish line, making me fail.