MarNee,
If you are referring to the scene view, this is normal behavior. The scene view camera also dictates the vertex positioning of the shader. I usually set the shader to a standard unlit while I'm working on the scene, and then back to curved before I publish or play the game. If you still have problems, let me know.
If you are seeing this behavior in play mode, you may want to try the following:
In the TrackCurveManager "Curve World" FSM, expand the Translate state. In each of your additional "Set Material Vector2 Floats" actions, you simply have to place a checkmarks on each action's "Every Frame" to enable a constant update of the material curve.
If you are still having trouble let me know.