From a short look, this seems to be caused by the fact that the cartographicDegrees array contains several duplicate points. This is only an observation for now, and I’ll have to read a bit more about whether this is disallowed by the specification, or what other options there could be for avoiding the crash. (It seems like DeveloperError: normalized result is not a number · Issue #4863 · CesiumGS/cesium · GitHub is related, but I haven’t read it thoroughly yet).
The following sandcastle does not contain duplicate points and seems to work:
It might not be “The Solution”, but maybe you want to do further experiments based on this observation.