https://docs.microsoft.com/en-us/windows/mixed-reality/mixed-reality-capture-for-developers#render-from-the-pv-camera-opt-in

1. What happened

With the above feature turned on, Mixed Reality Capture video is less stable than with it turned off.

2. How we can reproduce it using the example you attached

The attached project has an EnableAdditionalCamera script attached to the camera to turn on this feature. To see the issue:
1. Build the example for UWP.
2. Deploy to a HoloLens 2
3. Go to the Device Portal and record an MRC video.
4. By default, the MRC should be captured using the new feature, which shows off some instability.
5. You can also uncheck the Render from PV camera (or something similar) checkbox in the Device Portal to record a second video without the feature to compare stability.