I got Error while playing with sandcastle polyline CZML example

While playing with the Sandcastle CZML Polyline example I got the following error:

"An error occurred while rendering. Rendering has stopped.
DeveloperError: normalized result is not a number
    at new DeveloperError (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:540:19)
    at Function.Cartesian3.normalize (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:8146:19)
    at rotateVertical (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:187871:28)
    at Camera.rotateUp (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:187862:9)
    at rotate3D (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:233802:20)
    at tilt3DOnEllipsoid (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:234041:9)
    at tilt3D (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:233983:13)
    at reactToInput (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:232785:21)
    at update3D (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:234314:9)
    at ScreenSpaceCameraController.update (https://cesiumjs.org/Cesium/Build/CesiumUnminified/Cesium.js:234347:13)"

While playing with the example I choose "Cesium World Terrain" in the baseLayerPicker widget.

link to the example:

Does this happen as soon as you choose world terrain,or just when you move around in general? If it’s the latter, I think you might be running into this issue:

Just when I moved around in general.

Yeah it’s definitely something I’d love to see fixed. I’ll bump the GitHub issue so the team is aware it’s still a problem.