Why does it change to ECEF in runtime?

Whenever I click play in unity, the origin authority changes to ECEF coordinates automatically, even though I have set it as longitudelatitudeheight in the editor?

Attached two images of editor mode and play mode:

This is most likely caused by the CesiumOriginShift component attached to your DynamicCamera. It changes the origin of the CesiumGeoreference as the camera moves in order to keep the origin of the Unity coordinate system near the camera. When it sets the new georeference origin, it does so using ECEF coordinates.