Depth texture is unstable in post processing

Here is a screen record:

https://user-images.githubusercontent.com/22176164/216549800-9f46cdf3-7315-4673-bd00-5abf7ed2759a.mp4

Sandcastle example: [URL](https://sandcastle.cesium.com/#c=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)

Browser: Google Chrome 109.0.5414.120

Operating System: Windows 10 Version 21H2 (Build 19044.2486)

Any suggestions are welcome!

Start by opening the linked Sandcastle example in Chrome on Windows 10 and compare its rendering with the attached screen recording. Trace the depth texture behavior through post processing and verify the result across repeated frames; done means the depth texture and post-processing output remain stable.

Written by the indexing model from the issue text.