Camera can stay underground when 3D tiles load in

[ggetz]

What happened?

The camera is expected to stay above ground, even after higher resolution tile have loaded in. It possible to move the camera quickly when loading an initial view and get it to remain under terrain until the camera moves.

Reproduction steps

1. Go to the Google 3D Tiles Sandcastle
2. Use the geocoder to navigate to the Grand Canyon
3. Quickly move the camera down and underground before the view is stable

Environment

Browser: All
CesiumJS Version: 1.114
Operating System: All