The manual has some things to say about being too close to an object, saying that the end result may not look to good, the tracking my not be desirable. And they're right. The videos I've seen that are successful are also taken from farther away, higher in the sky.
It could be the tight corners at waypoints are the same thing -- they know that the don't turn out well, so advise you to use a less extreme setting.
It's possible that with the 2-second (or more) travel between shots, that tight pivot movement at a waypoint is just too jittery. Compare this to a video that is recording at least 24 frames per second.
Chris