Transparent object in .fbx file rendered by Qt3D disappears at certain camera angle

Reproducer is too large to be uploaded so I store it in OneDrive. Download the reproducer and it should be run on 5.15.13/14. I am not sure if the maintainers of Qt3D can see the link in my comment or can access it. Let me know if you can't.

Unnecessary codes are commented out from original project. Reproducer can be readily run on macOS/Linux but needs getopt.h on Windows. The .fbx model included is an automobile with all its windows/windshields separated as individual objects. SortPolicy is specified as BackToFront in CustomEntity.qml. Separation and sorting should be the necessary steps to ensure transparent objects being correctly rendered, I think.

What happens:
1. Play around with 'angle' property in BasicCamera.qml. The car windows look OK in most cases. But at certain angles slightly larger than Pi, e,g, Math.Pi * 8 / 7, the front window looks as if it disappears. Or uncomment the NumerAnimation component to see how the windows are rendered and issue happens with angle changing.
2. Change SortPolicy to FrontToBack. Then it is the back window that looks like disappeared.
3. Remove the SortPolicy. It solves the issue but I don't think it is the correct solution.
By 'disappear' I mean something like what the screenshot shows.