Entity Tracking sandcastle broken in 1.126

[srcejon]

What happened?

The Entity Tracking sandcastle appears to be broken in 1.126. Worked in 1.125.

https://sandcastle.cesium.com/?src=Entity%20tracking.html

It doesn't appear to track either the satellite or drone in any reference frame.

If I comment out the following lines:

satellite.viewFrom = new Cesium.Cartesian3(-300, 20, 100);
drone.viewFrom = new Cesium.Cartesian3(-50, 0, 5);

It starts tracking.

Reproduction steps

1. View https://sandcastle.cesium.com/?src=Entity%20tracking.html
2. Click drone
3. Camera doesn't track drone
   ...

Sandcastle example

https://sandcastle.cesium.com/?src=Entity%20tracking.html

Environment

Browser: Edge / Firefox / Chrome
CesiumJS Version: 1.126
Operating System: Windows 11

[jjspace]

I can confirm the issue is happening but haven't really looked into it. At initial glance I do wonder if it's related to this pr #12429? It was targeted at some changes to tracking entities so it's possible.

[jfayot]

You're right @jjspace ! Git bisect points to commit f01671e

[jfayot]

More specifically, restoring boundingSphereScratch instead of entityView.boundingSphere inside CesiumWidget._onTick fixes this issue...