`viewer.flyTo` has inconsistent behavior when flying to dynamic entity

From [this forum post](https://community.cesium.com/t/strange-viewer-flyto-behavior/13368). There are two sandcastles involved: [Sandcastle with **static** entities](https://sandcastle.cesium.com/#c=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) vs. [Sandcastle with **dynamic** entity](https://sandcastle.cesium.com/#c=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)

The user observed strange behavior in the Sandcastle with dynamic entities. The viewer overshoots / undershoots the entity that it is flying to, and often ends up underground. However, the first flight from Position 1 to Position 3 seems fine. Any other flights result in the camera going underground.

The Sandcastle with static entities works more consistently, but the first time that you fly to Position 2, the viewer flies underground. If you fly to any of the other positions, then back to position 2, it works as expected.

Browser: Google Chrome
Operating System: Windows

Start by reproducing the static and dynamic entity Sandcastle examples linked in the issue, following the Position 1, 2, and 3 flight sequences. Compare the camera behavior for repeated flights and inspect the viewer flyTo path involved in those examples. Done means flights consistently end at the target entity without overshooting, undershooting, or moving underground.

Written by the indexing model from the issue text.