Issue with Pessima Introduction scenario

The first four checkpoints work, but there's no fifth checkpoint. If you look at the json for this scenario, some checkpoints (the fifth being one of them) are not defined by the prefab but by referring to a segment of road, I suspect the issue has something to do with this.
Is this likely to be fixed by simply defining checkpoints in the prefab, or are you going to try to fix however it was that checkpoints were defined by road segments?