Strange Display Behavior of KML PolyStyle Fill = 0

I have a KML file that contains four polygons;
one for ‘Wind Confidence Lines’ with PolyStyle Fill = 0, and three for different ppms of ‘Threat Zones’ with PolyStyle Fill = 1.

When displayed in Google Earth Pro, it looks okay. However, when displayed in CesiumJS, the display behavior looks strange. That is, the ‘Wind Confidence Lines’ looks floating above the ground even if kmlDataSource has clampToGround property set true.

Here are the compared images of Google Earth and CesiumJS;

For the analysis, I also would like to share the source KML file(GasZones.kml) as attached.
GasZones.kml (19.1 KB)

Additionally, the CesiumJS visualization app is posted at Cesium Sandcastle - Cesium Sandcastle

Any advice to fix the strange display behavior problem is welcome.

Thanks in advance,