This had been tested, and thought to be fully working. Just to make sure i tested it again this morning. I found, i believe, your issue with a work around for you to try. Ooga is checking against spherical checkpoints to decide you are completing the course, and not cheating. We thought we had made them as tight as necessary, and in very safe positions seen here:
(forgive the terrible MSPaint. I don't have photoshop on this computer. Also keep in mind this diagram isn't entirely accurate to the scale of the checkpoints)
When I was able to replicate your issue i did it by double jumping the first lava pit completely avoiding the second sphere, which put you a sphere behind completing a lap. So, as a work around make sure your path takes you through all of those circles. Your best bet is to be as close to the ground as possible there, excluding the falling one, which you will be unable to miss.
Hopefully this helps, and if you need anything else let me know.